The Jolly Contrarian on Crime and Punishment

From all that terror teaches,From lies of tongue and pen,From all the easy speechesThat comfort cruel men,From sale and profanationOf honour and the sword,From sleep and from damnation,Deliver us, good Lord!G. K. Chesterton, O God of Earth and AltarA mystery persists. What is it about this waiver of privilege that so fixates everyone?It is plain, under current rules, Ms. Letby must waive privilege on the topic of fresh evidence, chiefly to determine whether this new material really is “fresh evidence” and, if not, why not, and why was it not presented when it could have been at trial?Ms. Letby’s new barrister, Mr. McDonald, is hardly shrinking violet. On most topics, he won’t be quiet. On this one, he is curiously reticent. It is a formal step, but he does not seem to have taken it. (We don’t know this, of course, but it is consistent with his public statements). It may be he has not yet been asked. But as the law stands, the appeal cannot get much further without it. If, as he says, Ms. Letby is innocent, there shouldn’t be anything to lose.Should there?The apparent hold-up alerts prosecution supporters — who are prone to this sort of thing — to the smell of a rat. Aha: the defence is hiding something.The privilege question brings together three large perplexities of this confounding case. They go along way to explaining why it is so controversial:* The missing defence evidence: If the prosecution evidence really was as flimsy as the “Letbyists“ say, why on Earth did Ms. Letby’s defence not present evidence to contradict it?* The copious trial: If the prosecution really was a farce, how on Earth, after ten months of eviscerating cross-examination, objection and legal submission, did the jury convict?* The privilege question: On the other hand, if Ms. Letby really is innocent — if this really is an epochal miscarriage of justice, then what does she have to lose from waiving her privilege?Thanks for reading! This post is public so feel free to share it.The innocent have nothing to hide“The innocent,” they murmur conspiratorially, “have nothing to hide.”From the outset, prosecution supporters — let’s call them “guilters” — have bridled at the very idea anyone might doubt Ms.Letby’s guilt. But, to their ongoing, suppurating chagrin they cannot produce a gotcha: there is no simple swingeing juridical sword that can slay this heretical campaign for once and all.What don’t you understand? She was tried and found guilty.Their mood has only darkened as the public debate as developed. In the town square, at least, the miscarriage campaign has only gained momentum. Every new turn seems to support it. The guilters’ ramparts continue to erode.“But,” they like to say, “in the town square, talk is cheap. Talk in a criminal trial is not.”This is right. Criminal trials are filtered, chaperoned and climate-controlled. Careless talk is not allowed. Every utterance is frisked. Every action must conform to common law principles honed over centuries with the single goal of isolating truth and reasonable inference from the “easy speeches that comfort cruel men” — just the sort of carry-on you will hear in the town square.The trial verdict thereby acquires a mystical status of higher truth. It is all that matters. It cannot be impeached by scurrilous tittle tattle in the taverns and bars — the kind of thing you are reading now.In this oasis of probity, after time and weighty consideration, a jury of twelve ordinary citizens found Ms. Letby guilty. What later discussion happens outside the marketplace — the hoary banter amongst squabbling fishmongers — is of no moment.Barristers are uncommonly fond of this view. Especially senior ones. But you can hold it for only so long: experience shows the courts can and do get things badly wrong. And when they do, they are notoriously slow to acknowledge it. Outrageously so. And when they do finally see the light, their change of heart is not, generally, occasioned by their own introspection. Rather, it arises because people outside the sanctuary — squabbling fishmongers in the town square, if you like — make an unholy racket about it.Unholy. I use that word advisedly. Often, until their change of heart, the legal system regards such efforts with contempt.But the “marketplace of ideas”, with all its squabbling fishmongers, is a good leveller: after all, cruel men can make easy speeches from either side of the aisle.[1]What is remarkable about the public debate, given the resounding nature of the convictions, has been its imbalance. It has been one-way traffic. In eighteen months, the guilters, though resolute in giving no quarter, have barely fired a shot. All they have is the trial. That is their citadel. But try as they might, they cannot turn up any incriminating revealers beyond it. Nor can they find anyone with germane expertise to corroborate the expert opinions the crown presented at trial.If Ms. Letby really is guilty, this, too, is a deep mystery.All the more surprising, because those finicky rules of criminal procedure are designed in large part to protect defendants: to prevent unfairly prejudicial inferences being drawn about the accused in front of a biddable jury.But now the jury has done its job and been sent home, there ought to be plenty of prejudicial inferences that, unbound by the court’s careful rules, guilters can lob about on social media. But — judging by the feeble dreck they do come up with — there don’t seem to be. As a result, public debate has been a piecemeal demolition of the crown’s case.And nor has it been just we legion of fishmongers and poundshop Poirots. In 2024, no less august an outlet than the New Yorker published 13,000 words questioning statistical misconceptions in the trial. Since then, a procession of world-renowned experts, from places as far-flung as Canada and New Zealand have intervened, unbidden, to support the defence.What would prompt recognised experts, apparently without recompense, to stick their necks out in support of a convicted multiple-murderer of premature infants?The best the guilters can come up with is that these experts are dupes — victims of, or complicit in — an “innocence fraud”. (This is a form of psychological mass manipulation they appear to have made up.)Capsizing the BayesiansThose speaking for Ms. Letby keep dragging the discussion back to probabilities. In the guilters’ eyes they ignore the “hard facts” of Ms. Letby’s trial and conviction.And, they remind us, none of these newly-arrived experts witnessed anything. (In fairness, nor did the prosecution experts who gave evidence at trial, a fact the guilters gloss over.) So these defence experts can only present their knowledge abstractly: they can say, “ah, yes, but the collapses could have been caused by this”; “It’s a lot more likely to have been that”, but they cannot tell us what actually happened.Guilters have found the hypothetical nature of these contributions exasperating.“What does it matter that she wasn’t likely to do it if we know she actually did it?”This rhetorical is a neat lay summary of Bayes’ theorem, by the way: the unspoken answer is, “it doesn’t matter a bit: if she did it, the improbability of that fact in the abstract is entirely irrelevant.”But — unless one is prepared to accept the trial verdict without question, and “Letbyists” aren’t — we don’t know she actually did it. The case is maddeningly lacking in concrete evidence. So, probabilities do matter.As the debate has moved on, those defence hypotheticals, those appeals to abstract probabilities over “proven facts” — the very lack of proven facts to settle things over way or another — has stubbornly remained, while the several circumstantial limbs of the prosecution case that grounded the original convictions have, one by one, given way.Her “confessions”, taken out of context from a morass of stream-of-consciousness scribblings that also asserted her innocence and victimisation, were nothing of the kind. The handover notes found under her bed weren’t “serial killer trophies” after all: by and large, they had nothing to do with the charges. The prosecution expert had his paltry understanding of air embolus symptoms, cribbed from a general and long out-of-date paper, perfectly backwards. The police misread door-swipe data immediately before significant events to have Ms. Letby entering the ward rather than, as was in fact the case, exiting it. Rather a consultant fortuitously discovering Ms. Letby standing inertly over a desaturating infant “virtually red handed”, the consultant’s own contemporaneous notes, not disclosed at trial, suggest Ms. Letby called him to the emergency. The insulin immunoassay equipment used to test samples was unreliable, known to throw out errors of exactly the magnitude of the readings cited by the crown as “smoking gun” evidence of Ms. Letby’s malicious intervention, and the tests were not rerun or corroborated.Not just one or two of the prosecution planks have been undermined: all of them have. There is a better, more likely, explanation for every one of the prosecution’s key contentions.These are not trifling issues. Even taken separately, they would throw significant doubt on the verdict. Together, they suggest the trial was fundamentally, fatally flawed.The tide of public opinion has, accordingly, turned. The dwindling band of defiant guilters hold out hope for a clinching fact that would torpedo all this confounded hypothesising. To reiterate: all abstract “prior” probabilities, however compelling, can be overturned by “posterior” fact: just one fact could do it, but the longer things drag on—the more everyone combs through the details, the less likely such it is such a fact would have lain undiscovered. We’ve been through the trial and eighteen months of fractious banter. The police have investigated tirelessly for a decade now: they are still going, they say, debating further charges. But nothing.Privilege as the final frontierThere is one last place no-one has checked. It is a place unusually likely to contain “killer facts”, what’s more: it is just the sort of place you might find a clincher. The record of private, candid communications between Ms. Letby and her criminal lawyers. This is, as we know, guarded by the sacred constitutional dragons of privilege. Ordinarily, they are impregnable.But here, by dint of a quirk of recent case law — arguably a bad statement of law, but let’s park that, because, for now, it remains good law — if Mr. McDonald wants to proceed, he must stand his dragons down.Guilters, therefore, turn their focus on Mr. McDonald. He seems to baulk at the very thought of waiving privilege. They are attuned to smelling rats and, in Ms. Letby’s strange hesitance to give way on this privilege question — and, really, that means her advisers’ reluctance[2] — think they may at last be onto one. What is he hiding?This, perhaps more than anything, gives guilters hope they will be finally vindicated. Mr. McDonald is sitting on a devastating “posterior” fact: a clincher no-one else knows that, being privileged, is impervious to enquiry, but which, if it got out, would blow all the defence experts’ careful hypotheticals out of the water, for once and for all putting Ms. Letby’s guilt beyond doubt.Common law rules require appellants with new legal advisers who wish to introduce fresh evidence on appeal to waive privilege as far as is needed to satisfy section 23(2)(d) of the Criminal Appeals Act 1968.That is to help satisfy the Court that there is indeed a reasonable explanation for the appellant’s failure to adduce the evidence at trial.Ms Letby’s trial counsel, Mr. Myers, must file what is called a “Gogana statement”[3] attesting to the evidence he had and did not have, what steps he took to find it and why, if it was available, he did not use it.These are all questions of great interest in this case.The “thin end of the wedge” argumentMr. McDonald’s publicly expressed view on why he is reluctant to waive privilege is different. It was reported in the Guernsey Press — why not? — as follows:If privilege is waived, they’re going to have access to every single conversation she’s ever had with her lawyers. You know what they did with her Facebook searches, and with a text message conversation she had with another doctor, Can you imagine if they had access to every single conversation that she’s ever had with her lawyers, all there in front of them, how that could be used against her, if there’s an inconsistency in something she said four years ago and has changed her mind in whatever way it may be? That’s your area of concern when it comes to waiving legal privilege? [4]In my view, for the little it is worth, this does not really hold water. Courts do not play fast and loose with privilege. The waiver would be limited to Mr Myers’ “Gogana statement”.All other communication with lawyers— everything except the specific question of what evidence was available and what good it could do her case — would remain privileged.So what are some other reasons to hesitate?The trial is that air-conditioned crucible of truth, remember: that is where opposing counsel can, within carefully developed rules, pick holes in the defence evidence. Or blow holes in it. The defence’s reasoning for not subjecting its experts to such an interrogation might be revealing.Mr. Myers might have told his client any of the following things:“This evidence is flimsy, and prosecution cross-examination could undermine it.”The “it’s feeble evidence” argumentIn their book, Unmasking Lucy Letby, Judith Moritz and Greg Coffey lean towards the first alternative: the defence did not lead evidence because what they had was flimsy, and vulnerable to cross-examination:Although Dewi Evans and Sandie Bohin did most of the heavy lifting in the prosecution’s scientific arguments, these other experts made their own contributions to specific parts of the prosecution case. That raises an obvious question: why did Letby’s defence not call their own army of experts — their own pathologist, their own radiologist, their own insulin expert, and so on? Did her defence team fail to seek out their own experts? Or — as in the case of Mike Hall — did Letby herself choose not to call any experts, and if she didn’t why didn’t she?I don’t doubt this is right, but nor does it really have much bearing on whether to waive privilege.The proposition here is that the defence went to get rebutting evidence at the time, and what they received from the experts they spoke to was not enormously encouraging. Given the nature of the prosecution evidence — itself speculative and hypothetical in nature — this is not surprising: no credible expert is going to refuse to rule out a remote possibility, so the defence evidence might be taken in a way to affirm the prosecution case, especially when framed that way by prosecution cross-examination and closing submissions. If you can’t land a knockout punch on the prosecution case, why open yourself up for a counter-jab?Experts consulted at the time may have been unenthusiastic about the prospect of going to extraordinary lengths to defend someone already portrayed in the public sphere as a likely monster — even radiologists are human, after all.But that was then. Public opinion has shifted. The panel of international experts now have been a good deal more categorical and have identified further nuances and medical subtleties that were not addressed at trial. They could have been addressed at trial, perhaps, but they were not. The Court may take something of a dim view here — but on the other hand, if a potential expert witness is not volunteering subtle and nuanced information, it is a bit unreasonable to expect a non-specialist barrister to recognise it: the very reason we have expert witnesses in the first place is because these things are not intuitive or obvious to the jury. Nor would they necessarily be to a criminal barrister.The Court has an option here: if it is not minded to hear the evidence, it has a justification for not doing so. If it is, it has the discretion to get over the hump. For all its formal insistence on analytical rules, the “temper of the times” will have a bearing here, and Mr. McDonald’s efforts to change that temper may be telling.In any case, this does not feel like a clinching argument to resist waiving privilege. The Court’s supposition will be that this evidence should have been presented at the time, and anything Mr. McDonald can present to explain why it was not must help — or elucidate his case — in some way.The “it undermines the defence case somehow” argumentThe second has been aired in the town square by barristers of some renown. It is not that the evidence itself is wrong, but it kicks away vital support struts for other aspects of her account of events. But since Ms. Letby’s defence has been “Beyond knowing it was nothing to do with me, I do not know what happened”, and since the evidence in question would be presented not to support her concrete account of events — she hasn’t given one — but to undermine a tendentious hypothetical theory advanced by the prosecution, it is hard to see what damage this evidence, or any evidence, could do, beyond just seeming a bit feeble. That alternative accounts conflict with each other does not matter when they are hypotheticals. What matters is that they, in the alternative, conflict with the prosecution’s case theory.The “I know she’s guilty” argumentThere is a third possibility. This one is viable — highly unlikely, but certainly not impossible. Perhaps trial counsel Mr. Myers was unable to lead this evidence, even though it is true and correct in itself, because doing so would mislead the Court. A barrister’s ultimate duty, over and above even his duty of privacy is to the Court.How could true evidence mislead the Court?Well, remember our Bayesian inferences and the probability conundrum we discussed earlier. There are background, or “prior” probabilities from which inference is possible in the absence of anything better — “statistically, what was the resting likelihood of murder, compared with some other benign explanation for the collapses?” — and then there are posterior probabilities — is there anything better that might adjust those underlying base rates? “What specific information is there that Ms. Letby did — or did not — cause the collapses that would undermine the “prior” base rate assessment?”If the defence knows of “killer” posterior facts — excuse the pun — that would render abstract hypotheticals irrelevant, then it would be highly misleading to present that abstract hypothetical evidence. It would be a serious breach of professional obligations.Mr. McDonald’s “fresh evidence” is hypothetical. It is all to the effect that “there is a far more likely explanation than murder.”It would be quite irrelevant if, for example, Ms. Letby had made it clear to her counsel that she had, in actual fact, attacked the infants. If she had told her lawyers:“Between these four walls, you should know that I So great is the Court’s reverence for form over substance, that it will tolerate this absurd hypothetical. (I do not for a moment think this happened, but it could.) Such a defendant could ask her counsel to take her case.But counsel would be bound by the overriding duty to the Court. He cannot mislead the court, but nor can he let the court in on what Ms. Letby has said. He can say to her:“I can defend you, but only by putting the Crown to proof. The Crown, and not you, has the burden of proving the charges. If it cannot, you will walk free. I can make them prove their case, and I can do my best to challenge their evidence and counter their arguments. But I cannot make a positive case for you. I cannot present alternative hypotheticals that I know to be untrue.”Wrap upIf this is right then the guilters have their smoking gun. As long as Mr. McDonald has being cagey about it, they will hang on to this conviction: at this point it is pretty much all they have. It explains the mystery missing defence evidence, and it explains the hesitation over waiving privilege now. This is the “killer fact” that could emerge from even a narrow waiver of privilege.Still, it is extremely unlikely for a number of reasons, the main one being that if it was inappropriate to lead evidence about misleading priors then, then it would be no less problematic to lead it now. If the defence knows Ms. Letby did these acts it cannot lead evidence supporting the proposition she might not have. But clearly Mr. McDonald does want to introduce it. He plainly sees it as his best and most powerful tactic. He cannot regard it as misleading.And let us not forget his predecessor Mr. Myers went into trial fully intending to present defence evidence — as is evidenced by Ms. Moritz investigative journalism — which is why this is even a question. Mr. Myers submitted witness briefs at a pretrial conference of expert witnesses. He had his own expert, Dr. Hall attend trial throughout and seems to have made decision not to go with it at the last minute. There are sound reasons for not leading underwhelming evidence that may have done more harm than good.And, Mr. Myers tried to introduce Dr. Lee’s evidence about air embolism in an appeal. This is not consistent with his knowledge of Ms. Letby’s malicious action. He would not have done that — he would hardly have mounted an appeal at all — if Ms. Letby had been convicted of offences for which he knew she was guilty.But if the real reason for withholding was that the trial witnesses weren’t coming up to brief, why the reluctance to waive privilege? Why not say that? Things have changed. The evidence available now is much stronger. There is an army of leading academics behind it.What is most baffling is the “PR” value is all of this. Mr. McDonald has, to date, been canny with his PR. But he is losing on this one. The speculation that he is hiding something — and guilters are making a meal of it — is corrosive. The longer McDonald delays, the more that speculation hardens into its own narrative: “The defence is hiding something.”Nobody — but Mr. McDonald and his team — knows. Only Mr. McDonald can shut this debate down.After all: if it were true — if Ms. Letby had somehow copped to these awful crimes — then we should all want to know that. Gulling scores of distinguished experts into unwittingly defending a confessed murderer would be grotesque. It would be an outrage. The Court deserves to know. The public should know. This debate should, either way, be ended.But if it’s not true — and I don’t believe it is — Mr. McDonald needs urgently to take back control of the narrative and quell this speculation. He can do that by doing exactly what the law requires: advising Ms. Letby to waive privilege on the narrow question, have Mr. Myers file his Gogana statement, and put the matter to bed.This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

Trigger warning: this newsletter assumes readers are of sufficient maturity to understand and not be wounded by cultural references to cocaine, Starsky & Hutch, and physical money made out of paper. Also: these events happened a long time ago. My recollection is imperfect, and I have definitely changed and embellished the narrative to make it a good story.Dirty banknotesShe don’t lieShe don’t lieShe don’t lieCocaine.J. J. Cale, CocaineThere is an urban myth that every bank note in circulation has traces of cocaine on it. Except, it isn’t an urban myth: it’s a fact. I know it is a fact because about 15 years ago I sat on a jury in Wood Green and listen to a police forensic expert have to admit it under cross-examination during a criminal trial.The trial concerned a gentleman from Tottenham who, the Crown alleged, had been dealing drugs. He did this, according to the indictment, from a car parked in a secluded side street off the North Circular.The case rested on three items found in the defendant’s possession: a wallet stuffed with cash, a set of portable electronic scales and, as I recall it, 79 individually wrapped “rocks” of crack cocaine.It seemed open-and-shut. The Crown called a police forensic scientist to give technical evidence about the cash.Firstly, there was a lot of it. A little over £5,000: a good deal more than you might expect a gentleman of the defendant’s prospects to be carrying around North London at three in the morning. Secondly, it was generously dusted, the witness said, theatrically clearing his throat,With a substance that mass-spectrometry revealed to be a mixture of sodium bicarbonate and methyl-3-benzoyloxy-8-methyl-8-azabicyclo-octane-2-carboxylate —At this the witness paused, for dramatic effect. The judge looked non-plussed. The jury waited for the punchline. He gave it, triumphantly:Which is commonly known as crack cocaine.Every single note was, in his telling, caked with the stuff. We of the jury were resolute. This witness was clearly an expect. He had used reliable scientific tests. He was convincing. There was little doubt what he said was true.But then the defence barrister stood up. His cross-examination ran along the following lines.Defence: In your professional experience, Mr. Henhouse, would you say it is common for banknotes to be contaminated with cocaine?Witness: It is not unheard of.Defence: But is it common?Witness: I suppose you could say it’s common, yes. I don’t know.Defence: Roughly how common?Witness: Ooh I wouldn’t like to guess.Defence: No, I dare say. But indulge me. What proportion of banknotes are contaminated with cocaine?Witness: Well, A fair proportion, certainly.Defence: What counts as “a fair proportion”?Witness: A lot, I suppose.Defence: It’s all of them isn’t it?Witness: I don’t know. Look, I haven’t check every banknote in circulation, have I?Defence: Of course you haven’t. Of course not. But how many have you checked, over your [theatrically checks notes] twenty-seven-year career as a forensic expert? Ten thousand? A hundred thousand? A million?Witness: I should say tens of thousands, yes.Defence: And in those tens of thousands, have you found one used bill that didn’t carry traces of cocaine?Witness: (Mumbles inaudibly)Defence: I’m sorry, Mr. Henhouse, I couldn’t hear you.Witness: No.Defence: No further questions, m’lud.It was beautiful.How banknotes get cocaine on themNow, I’m sure none of my regulars readers will know this, but banknotes are sometimes used to snort cocaine. (Those who do know this presumably found it out, as I did, watching Starsky & Hutch in the 1970s). This is how they get cocaine on them.Not every banknote in circulation has been used to snort cocaine. Nothing like it Rather, cocaine is fine, rather adhesive stuff. It gets everywhere. It tends to rub off on anything it touches. Such as nearby bank notes. Since even law-abiding citizens tend to keep their banknotes together, in a wallet, a contaminated note has plenty of opportunities to rub against innocent ones.Law-abiding citizens also have a habit of passing banknotes around. The will just give them away, to perfect strangers, in a way they won’t, so readily, with their other possessions. A large part of the JC is devoted to why and how humans do this, and what it all means: we need not dwell on it here.In any case, one encoked banknote is likely to come into contact with, and infect, many “innocent” ones over its lifetime. This means many law-abiding citizens — basically all of them, according to this police scientist who had sworn upon a bible — regularly carry cash contaminated with a classy recreational drug. [Shouldn’t that be, “Class A recreational drug”?— Ed].Electronic scales of justiceThat was one piece of evidence presented — if reluctantly — in the trial. Another was that British drug dealers weigh and package their product using unremarkable consumer durables: digital kitchen scales. These scales, so said the witness, are plenty accurate enough to prepare and apportion crack for retail distribution.I was quite pleased to hear this. It speaks to attention to detail and a commitment to quality control I would not have expected in the criminal class. It is laudable in its way. Plus, those digital scales are neat. We have some in our kitchen. We keep them in a draw with the used chequebooks, spaghetti, dried up felt-tip pens, mysterious keys, broken utensils and ant poison.When the police apprehended the defendant, in his car, parked under a tree beyond the throw of the nearest street lamp, they found some Salter electric scales in his glove compartment. These they bagged up, labelled and presented to the court as “Exhibit A”.In the manner of a conjurer gulling an unwitting accomplice, the prosecutor bade a court official pass the scales, in their bag to the jury for inspection. I was surprised, and rather pleased, to see it was exactly the model we have the Contrarian household’s keys, pens, spaghetti and ant poison drawer.The final exhibit — which the court official did not hand over for inspection, for some reason: we were invited to regard it from afar — was 79 individually wrapped “rocks” of crack cocaine.The same police analyst explained what a “rock” is (one tenth of a gram of cocaine mixed with baking soda), and that its street value was about £2,000. The arresting constable had already testified that he found these in the defendant’s jeans pocket. This was before the era of always-on bodycams, but the defence did not dispute it.These were the uncomfortable circumstantial facts that the defendant’s barrister had to deal with: how to explain what his client was doing in a parked car in a secluded spot, in possession of five large in cash, a set of digital scales and enough cocaine to entertain most of Crouch End for a fortnight, if he wasn’t planning to sell it to people.To be sure, the facts were all circumstantial: no one saw this fellow supplying anyone with any drugs. It required inference. But, as the prosecutor would suggest in his closing submissions, it was not a hard one to draw.Then began the case for the defence.The defence caseThe defendant turned out to have a rather ingenious barrister.[1] His strategy was threefold.Firstly, with the unwitting assistance of the police’s own expert, he established that coke-contaminated bank notes are not in themselves evidence of anything. Even the police conceded that, as far as anyone knows, every bank note is coke-contaminated.Secondly, he made a complex submission that, while possession of large sums of money or large quantities of crack invited, to some degree, an inference that their holder for the time being was a drug dealer, having both at once did not: one is tendered in exchange for the other, after all. While the possession of both money and drugs no doubt invited some adverse insinuations about the defendant’s character, that he was supplying drugs to customers on a commercial basis — the offence for which he had been charged — was not one of them.There are obvious flaws in this reasoning — we in the jury saw them at once — but they flummoxed the poor prosecutor, who looked quite blindsided by this submission and was unable to make anything of it.The defence’s last zinger came in cross-examination. It was a master class in the ancient art. Once again, the victim was the same benighted forensic scientist, brought out, so he thought, to establish uncontroversial scientific facts about cocaine and banknotes, and who was already having a miserable day, which got worse when, against his expectation, the cross-examination turned to the kitchen scales.It went like this:Defence: The device recovered from the defendant’s car is a set of ordinary kitchen scales?Witness: Yes, I believe that is right.Defence: Salter ‘ARC’ electronic scales.Witness: I’ll take your word for it.Defence: These are ordinary kitchen scales — the sort of thing that anyone might own. Even members of the jury?Witness: (Observing several jurors nodding vigorously) Yes, I dare say.Defence: But they are also commonly used for measuring up quantities of crack?Witness: (Brightly) Yes. Yes I believe that is very common.Defence: Where do drug dealers usually measure up and package their supplies of crack?Witness: Well, I have no idea, as you can appreciate.Defence: But if you had to guess? Would they do that, do you think, somewhere private, secure, well lit, perhaps with clean hard surfaces? A controlled environment?Witness: Yes, I suppose so.Defence: Like a car parked in dark street?Witness: Well, I couldn’t rightly say —Defence: If you were a drug dealer, would you prepare crack in a car parked up just off the North Circular?Witness: Well, no —Defence: No you wouldn’t, would you? That would be absurd. I mean, just imagine it. Coke would go everywhere! Disaster!Witness: Yes, it probably would be quite messy.Defence: Yes! Quite messy! And as you have told us, cocaine is powdery stuff that gets everywhere, sticks to everything it comes in contact with?Witness: Yes.Defence: And detecting small quantities of cocaine in the lab is a cinch?Witness: Yes, that is right.Defence: And you say the defendant was there, measuring out rocks of crack with these scales, in the dark, on his lap, in the driver’s seat of his Cortina, at three in the morning, in Bounds Green?Witness: Well, I didn’t say th—Defence: Did you find any traces of crack on the scales?Witness: What?Defence: I said, did you find any traces of crack on the scales, Mr. Henhouse?Witness: Well, no —Defence: Did you even test the scales, with all your sophisticated forensic equipment? Did you even look for any of this easy-to-find crack cocaine?Witness: No.Defence: My lord, I have no further questions.It was spectacular theatre. The jury was riveted. And in each of our minds we posed exactly the questions the defence barrister wanted us to, and in our minds we answered them exactly how he wanted them answered, without having to put the questions to the witness at all.The time for closing submissions arrived. As a group we had little interest in what the prosecution had to say. The Crown’s case was obvious. It barely needed closing submissions at all. But we were fascinated to hear from the defence barrister.He did not disappoint.His first submission was that cocaine-contaminated banknotes meant precisely nothing. He suggested that each of us was carrying cocaine contaminated banknotes as he spoke.Then he turned to the kitchen scales. The Crown had conceded, he noted, that a drug dealer had no reason to have kitchen scales in his car. It was singularly preposterous to think he might be measuring out crack on the kerbside. Nor had anyone even asked the defendant what he was doing with a set of kitchen scales. It did not come up in cross-examination. By any measure the scales, he said, were irrelevant. One could not draw any inference about the defendant’s possession of an ordinary consumer durable.The crux of this long but, I hope, entertaining story arrived a bit later that afternoon when we sat down in the jury room to deliberate. I have done jury service twice in my life. It is a fascinating experience: I recommend it to anyone, just as an opportunity to witness how communities form and operate. Out of, perhaps, a surfeit of caution, I have excised any discussion of what went on within the walls — so far as I can even remember it — but the discussion is just as effective in the hypothetical. What follows is hypothetical.The first few moments of a jury’s formal deliberation are critical. A social hierarchy must form, from nothing, on the spot: twelve complete strangers are locked in a room and assigned a grave task. They do not know one another. They have no history. They are blank slates. Their skills, weaknesses and proclivities are unknown. They are, in every sense, equals. There is no organising principle. But this state of equanimity dissolves almost immediately. There are extraverts and introverts. There are logicians and feelers. Judgers and perceivers.Quickly this disparate group self-organises into a social unit with a clear hierarchy. You can imagine a person starting off the discussion like so —I have no doubt he’s guilty, but I don’t think the police has proven it.Quickly, others might join in:Yeah, I mean bang to rights — five grand street value of crack? How is that guy not a drug dealer? But the police were really useless.I would have felt the same way. You could see how, where the perceived social ill is quotidian, people could be incentivised to “send the police a message”: there is form and there is substance, and it is one thing to prefer form over substance, but if you can’t be competent to at least get the form right, you should not be subjecting people to the criminal justice system.In my story — and to be clear, again, it is a story, loosely based on dim recollections, and designed to illustrate a psychological point — there are plenty of nods and winks to a fundamental fact: on the whole, Londoners are not that bothered about the supply of illegal drugs. Many quite like it. For all I know some of the jurors may have been casual drug users — even enthusiastic ones. Wood Green is not far, as the crow flies, from Crouch End. But the law is the law, and juries generally understand their duties well enough.Now the reason I mention all of this is that this liberal disposition to give a defendant the benefit of doubt — even unreasonable doubt — is more likely to happen in some cases than others.There are times, like this, where a jury will positively seek excuses to acquit a defendant. Here the prosecution must not only have a rock solid case that really is, in fact, justified, but they must follow every procedural step to the letter. Any slips, formal or substantive, and they will fail. This is where the charges brought are, technically, against the law, but the jury has limited sympathy for the law. There are many laws on the books that have limited public support. Sunday trading laws, for example.Appalling vistasOur fathers claimed, by obvious madness movedA man’s innocence, until his guilt is provedThey would have known, had they not been confused —He’s innocent until he is accused.—Ogden Nash, Period PeriodBut there are other times where the opposite happens: some law reflect deeply-held community values. Murder, for example. The murder of the vulnerable by those in positions of trust. I have a theory that murder laws do nothing to change the murder rate: those of us who refrain from murder do not do so because there is a law against it. It is a deeply held moral conviction that the law simply reflects. Would that all laws did this.Where acts alleged are deeply repellent to their personal values, no jury will acquit “just to send the police a message”. In fact — so the academic literature tells us, and it resonates as common sense — quite the opposite. When allegations are monstrous, the jury’s nervousness will be about acquitting, not convicting. The jury will be fearful of unwittingly letting an actually guilty defendant go free.A 2018 study[2] in Nature’s Human Behaviour imprint revealed just this bias in mock jurors when asked to consider hypothetical crimes of different severity. The more heinous the crime, the more likely subjects were to be convinced by the same amount of evidence.This correlation applied across all participant groups, but was much greater for mock jurors than for prosecutors and other legal professionals. This suggests that emotional and moral reactions to the severity of allegations may unconsciously lower the evidentiary threshold jurors apply when determining guilt.Better the odd innocenti gets banged up than a single monster goes free.This is a jury’s equivalent of Lord Denning’s notorious “appalling vista” rationalisation in dismissing the appeals of the actually innocent “Birmingham Six”.If the six men win, it will mean that the police are guilty of perjury, that they are guilty of violence and threats, that the confessions were invented and improperly admitted in evidence and the convictions were erroneous ... This is such an appalling vista that every sensible person in the land would say that it cannot be right that these actions should go any further.The jury will have felt the same. Terrorism is repellent: not morally so much as personally. Even terrorists have their causes, but we have a selfish interest in their being safely behind bars, and in the agency that put them there being uncorrupt, nonviolent, expert and excellent at identifying and apprehending the right villains and if not that, then at least basically competent. We want to believe that such an agency would not charge the wrong people, inadvertently or wilfully. To acquit such a defendant is to suppose, in the best case, that government agencies are catastrophically failing. And that is if the acquittal is correct. To falsely acquit is to believe murderous terrorists over the upstanding agencies of the state. Who takes that risk? Where does that leave us? Lord Denning was right: this is an appalling vista. He was only wrong in stating we should therefore close our eyes to it. He was very, very wrong about that.But, by comparison, terrorism is an easy case. Where the allegations are morally repugnant — where a jury of citizens is protecting not its own selfish interests but rather guarding the vulnerable from the wickedness of those to whom their welfare is entrusted, our instincts are emotional and the logic is even stronger. If what is alleged is truly horrendous, the victim defenceless, the idea of acquitting a defendant whom we think may be guilty is repellent.If we believe a defendant is guilty, but are not “sure” the law of the land says we must acquit. We might, enthusiastically, for a gentleman caught in a Cortina in Bounds Green with a wad of contaminated bills — but would we for an alleged child murderer?See also* Lucy Letby* Burden of proof* Circumstantial evidencePlaylistWell — it couldn’t really be anything else, could it?This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. 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The investigation into the actions of Lucy Letby, the trial process and medical experts continues to face scrutiny and criticism, much of it ill-informed and based on a very partial knowledge of the facts and totality of evidence presented at court and at the Court of Appeal.This case has been rigorously and fairly tested through two juries and subsequently scrutinised by two sets of appeal court judges. Lucy Letby’s trial was one of the longest-running murder trials in British criminal history with the jury diligently carrying out their deliberations for more than 100 hours.It followed an investigation that had been running for six years – an investigation like no other in scope, complexity and magnitude. It was a detailed and painstaking process by a team of almost 70 police officers and no stone was left unturned.Preparing for the trial was a mammoth task with 32,000 pages of evidence being gathered and medical records running into thousands of pages being sifted through. Around 2,000 people were spoken to and almost 250 were identified as potential witnesses at trial.As the case unfolded, multiple medical experts – specialising in areas of paediatric radiology, paediatric pathology, haematology, paediatric neurology and paediatric endocrinology and two main medical experts (consultant paediatricians) – were enlisted to ensure that we carried out as thorough an investigation as possible.All are highly regarded in their area of expertise and were cross-examined whilst giving their evidence in court.—Detective Superintendent Paul Hughes, Cheshire Police, 2 April 2025.Thanks for reading! This post is public so feel free to share it.Often spotted in the trenches as the keyboard war rages over Ms. Letby’s conviction — I have seen action — are variations on this argument:You were not at the trial. Unless you sat through ten months of evidence — unless you saw everything the jury saw, and looked into the whites of the defendant’s eyes — which were yellow, come to think of it — you simply cannot know the facts and cannot form a useful opinion on her guilt. It is beyond you.Advanced by those who also were not at the trial and who, by their own logic, have no better idea of what went on, it really amounts to saying:“I find the trial’s outcome agreeable and wish to entertain no further debate about it.”ImpermeabilityLike all Anglo-Saxon criminal trials, Ms. Letby’s was conducted according to arcane rules: common law, statute, the rules of criminal procedure, the law of evidence, and long established (if roundly criticised) principles governing the use of expert witnesses.These institutions are meant to, and generally do, vouchsafe justice, but are not infallible. Miscarriages of justice happen. Even outrageous ones.From this tremendous melée — the evidence-in-chief, cross-examination, submission, objection and each fork-tongued duel between barrister and witness — we expect 12 random citizens to form between them an impression sure enough to condemn a defendant — but yet at the same time so mystic and ineffable that it cannot later be explained, interrogated or rationalised. The verdict passes intractably into the record, a brute ontological fact, immune to later mortal analysis.To the question:How on Earth did she get convicted?Comes the answer:You had to be there.The Holy Spirit was upon these jurors. It may have taken 22 days — if that in itself does not indicate reasonable doubt, what would? — but a guilty soul was justly condemned. Justice came, did its thing, and went. It left no trace. None can now make sense of it. We should not try. But still we must, all the same, quietly abide. The senior bar will be most discomported if we do not.What the eye don’t see —Acurious feature of this argument is how it depends on what we cannot see. There is a “truth”, but it is composed of darkness. We cannot apprehend it, so we cannot challenge it.Before a verdict, explicitly, the criminal law does not work like this. Quite the opposite: it is all daylight and backlit halogen lamps. It is, to a fault, transparent, rational and unflinchingly evidence-based: facts are the be-all and end-all. But only the best kind of facts: there are strict rules governing what may be admitted.All facts put before the court may be interrogated. Everything that can influence an outcome must lie on the surface. If it cannot be made to float — if it comprises innuendo or prejudice, it must be sponged from the record.Nor may the opinions of those not in the jury box intrude. Juries, rarely, may be sequestered: news organisations are heavily constrained, on pain of contempt, in what they may say. They may only repeat, colourlessly, things the jury has heard. Social media makes this quite a nightmare.In a criminal court, everything the jury hears is open to audit. Anything that is not is disallowed. Until the moment the jury withdraws to begin its deliberation, nothing in a criminal case can defy comprehension. Darkness is not allowed.Until the jury retires.Lucy Letby’s trial ran for nine months. The jury deliberated for a month after that. They had a colossal amount of data. Their task was Herculean. It was beyond any reasonable expectation we might have of twelve ordinary men and women.They should be commended for their work, but it is not beyond our comprehension. It is not to say that the material grounds for their decision cannot now be summarised, analysed or criticised.Indeed: that is the very trial process: both prosecution and defence summarise their positions and present them to the jury at closing. Then the judge sums that all up. That took the best part of a month, too.So if we who were not in court ask the question now:How on Earth did she get convicted?Someone ought to be able to give sensible answer.At the time of the original trial, in the public’s mind, there was a sensible answer. It went something like this:It was proven in court:These are good grounds, if true, but they have been under sustained attack at least since Rachel Aviv’s New Yorker article of 13 May 2024 brought concerns about the convictions into the mainstream. The concerns were already there: a hardy band of campaigners — “Poundshop Poirots” in Dr. Evans’ phrase, “a strange band of misfits and ghouls” in Liz Hull’s — had been questioning the trial rationale since long before its verdict.The New Yorker piece created quite the brouhaha: indeed that is the first time I became aware there were any questions about the verdict.At first, senior barristers came out to defend the system. They were dismissive of the concerns of those not steeped like an old tea-bag in British criminal procedure.But the Poundshop Poirots were not deterred. It turned out not all were “fanatics and pseudo-scientists” as Liz Hull’s piece in the Daily Mail described them: quite a few were recognised professionals in law, medicine and statistics, some with significant experience in miscarriage of justice cases.The brouhaha carried on. It is still going, to this day.After more than a year of sustained interrogation by dozens of world-leading experts — see panel — as well as the misfits and weirdoes of Liz Hull’s imagining; of examination of trial transcripts, court reports, medical reports, judgments and appeal decisions the grounds on which Ms. Letby was convicted do not seem to hold much water.What is just is significant is this: in the 15-month period since the New Yorker article, despite an equally active group of internet sleuths, journalists and advocates defending the verdicts, not one new fact or opinion has emerged that unequivocally supports the facts and opinions the prosecution led at trial. The prosecution has its stout supporters, but beyond the original trial participants, none are medical experts, statisticians or lawyers. Their support is fully limited to defending the outcome of the actual trial as it was litigated. There is no outside support for the wider proposition that Ms. Letby actually murdered these infants.The defence is, in other words, strikingly formalistic: it is not a defence of an abstract question of substantive justice — is an innocent woman in prison — but of the formal qualities of a specific procedure — did her conviction adhere to the posited formal requirements of criminal procedure?But justice not only has to be seen to be done. It has to actually be done.Now: even if she were innocent, you would expect some uncomfortable material to emerge about Ms. Letby — no-one is perfect, after all. But it has not. There have been hints and intimations of further charges but they have notably lacked detail and were accompanied by no fresh evidence or opinion.Since the verdict was handed down, those supporting it have done so purely on the material presented at trial. They have rejected out of hand all subsequent commentary, however qualified, as if only the blast furnace of trial scrutiny can give evidence the necessary tempering and logical rigidity to stand as fact: nothing less, however carefully articulated or eminently authored, can match. Those who were not present cannot even understand.So the refrain still rings out:You had to be there.Now, to be sure: journalists can overplay their hands. We are in the age of clickbait. One so minded could sift through the record, cherry-picking facts from quotidian contexts to make a sensational story-line. One could blow trifling discrepancies out of all proportion. One could confect the wholly false idea of an injustice. But this is hardly the New Yorker’s style.But when the reputation of the British criminal justice system is in the, er, dock, it is right to pause for breath, and say something trite, like:“Extraordinary claims require extraordinary evidence”.They certainly do.Extraordinary evidenceBut then the extraordinary evidence started rolling in. To their credit, the blustering KCs walked back their early essays. One, having at first declared himself satisfied with the conviction, openly pondered whether we had another “appalling vista” on our hands.Statisticians picked up on the Texas sharpshooter aspects: The New Yorker was right: the spreadsheet was assembled to advocate for the theory that Ms. Letby was the perpetrator: the CPS appeared to concede as much in court.Lawyers questioned the operation of the expert evidence rules: the weakness under cross-examination of the prosecution witness and the strange absence of any defence experts.Forensic scientists challenged the insulin evidence.Those few with expertise in the field roundly debunked the prosecution expert’s evidence on air embolus, which fundamentally misunderstood the literature he purported to rely on.A degree of frantic dissembling came back over the trenches — the case didn’t hinge on statistics or the evidence of a single expert, it was claimed — but these deflections came largely from journalists, not credentialised experts. Few engaged with the meat of the criticisms being aired against the convictions, other than to say “these things have not been tested in court”.In matters of great public debate — at least, where there is an arguable case — we are used to experts lining up on either side to make their case. Even though the prosecution had succeeded at first instance, that did not happen here. The crown’s actual expert witnesses stood their ground, doggedly refusing to budge on any of their conclusions, even if their reasoning changed as needed to suit the emerging fact patterns.But no new experts, not already involved, came forward to defend the prosecution. This was despite energetic efforts from contrarian news sources — notably Private Eye — who have repeatedly appealed for experts to corroborate the views presented in evidence to support what would, presumably, be an easy status quo. None have.Now, since the NHS is the largest employer of medical expertise in the UK and the Crown Prosecution Service the largest user of professional expert evidence, we might put this down to professional courtesy, or even self-interest — a reluctance to bite the hand that feeds, so to speak — were it not for the fact that medical experts from around the planet were queueing up to challenge the CPS and NHS narrative, free of charge. It was just no one was lining up to support it.I have been running an informal log: see the panel. Over fifty well-recognised experts in their respective fields of neonatology, endocrinology, statistics, forensics and law have expressed misgivings about the outcome of this trial. Outside actual witnesses, just two have publicly supported the verdict.Are all these international experts labouring under a delusion? Have they been misled by nefarious interests into expressing formal, reputation-jeopardising public doubt — and in which case, whose, how and most importantly why? Who has anything to gain from guilelessly advancing the interests of a convicted serial killer?Again, the same question: why is it that no-one can explain what is so compelling about this verdict?“You weren’t there, so you can’t understand” really will not do.— the eye can’t critiqueJustice has, formally, been done. Convictions have been entered; barring the clement machinations of the Criminal Cases Review Commission — don’t hold your breath — appeal pathways are shut.But convicted criminals do not go into an oubliette. Once they are sent down, the justice system is not excused from explaining itself. After the verdict, any citizen who asks should get a straight answer: how was the system satisfied the criminal did what the Crown alleged?A criminal conviction cannot be some opaque, unspeakable, sacred mystery. It is the exact opposite of that: criminal justice is scrupulously analytical. The prosecution must painstakingly prove out every point in its chain of logic. It must all be disclosed in advance, laid out before the court, and opened to the defence, for its unlimited scrutiny.It is often said that the burden of proof inverts upon conviction: the Crown’s burden is satisfied; now the defence must discharge a burden to overturn a conviction. And so it must, but only to the balance of probabilities — though if a defendant wants compensation for her false imprisonment, she must prove her innocence beyond reasonable doubt.Never mind compensation: it is hard enough just to get out of clink. The Court of Appeal asks more that just a better job of stating your case: if no procedural irregularity or legal error, you cannot just have another go at explaining why the Crown’s evidence is unreliable. The jury has decided. You must present new evidence, not reasonably available at trial, to shine a new light, that the Court is persuaded might have changed the jury’s mind.While its appeal powers were crafted widely, the Court of Appeal has consistently interpreted them narrowly, creating binding precedents for itself. It will not do that you didn’t introduce evidence first time around: you must show that you couldn’t have. In this way, a defendant is beholden to her counsel’s competence and strategy.It is said that there are sound policy reasons for this: the law must dispense certainty. A vital aspect of criminal justice is finality. We do not want vexatious criminal ne’er-do-wells cluttering the system with spurious appeals.Indeed, no: but it is different if they are, in fact, innocent. If you have misconfigured your frontline system to routinely convict law-abiding citizens, the least you can do is install a quick and reliable “undo” feature. However you look at it, statistically, the justice system is designed to convict the occasional innocent person. Not even by accident.The criminal justice system has evolved a highly formalised methodology. More than most institutions in modern life, it stands on ceremony. But as all formalised systems must, it has escape valves. It can deliver discretionary clemency where its formal systems have created a manifestly perverse result. It is a discretion the Court of Appeal is notoriously reluctant to use: the idea that the sound operation of criminal procedure, in a high-profile case like this, could produce a manifestly perverse result is a “vista” too appalling to countenance.Senior barristers recoil at the suggestion that British justice could fail that badly. But disdain cannot obscure the fact that recently, it has failed this badly. Repeatedly. Just ask 900 odd sub-postmasters.All the same, the defence must make a compelling case. Whereas the prosecution may now make wan allusions to the unknowable genius of a bygone trial, if it wants any traction, the defence must, at this stage present detailed, specific and compelling arguments.Leaving aside for a moment the formal rules governing whether the criminal system is prepared to hear them, plainly, it does.Defence arguments are clearIn sharp contrast to those who would defend the convictions, Ms. Letby’s defence team has been garrulous. There have been interminable press conferences. Their arguments — many of them made “in the alternative”, as lawyers like to do, affording themselves multiple, sometimes contradictory, shots at the same target — have been published in tremendous detail. The defence has invited detailed rebuttal — some have, rather feebly, tried to provide it. Ms. Letby’s new barrister has shipped no small amount of professional criticism from his fellow barristers, not for being somehow covert, but for not being covert enough. Mr. McDonald is seen as being too forthright. Barristers, it is felt, should not court the media. As far as some members of the bar are concerned, it is just not cricket. But with a Court of Appeal as hostile to defendants as this one is, one can hardly blame him for thinking outside the box.The same goes for all the “strange band of misfits and ghouls” who have questioned the safety of the conviction. Their arguments are, by nature, public, detailed — way too detailed in many cases — specific, articulated, and anxious for attention: that is so say, welcoming of scrutiny and good-faith challenge.There has not been much. Credible challenges that have come back have been either formal in nature: “the rules have been followed, she had her chance, alea iacta est,” and so on — or somehow mystical: there are things that resist intellectual inquiry and must not be disturbed. Some things should not be said. Some questions should not be asked.This is especially perplexing since, generally, it is the prosecution who must make the intellectual running. The burden of proof lies upon the Crown, not the defence. A prosecutor should be better placed to spell out the ingredients of her case than a defender is to rebut it in the abstract. How do you prove a negative?That the burden reverses on conviction does not alter this fact.If the evidence was so compelling, and the Crown’s case so immaculate, you would think, someone would be able to explain it.The defence is well able to explain itself: its spokespeople can scarcely shut up. There are any number of erudite criticisms of the law, the application of evidence, the use of statistics, of the crown witnesses’ speculative diagnoses, available in the public domain.So where is the patient exposition of the Crown’s position: sure: the Crown Prosecution Service might not be minded to provide it, but someone?“If you weren’t at the trial, you can’t know”.This is a kind of “emergence” argument. It is routinely run, ironically enough, by people who also were not at the trial. How can they know any better, but by blind faith that the system will work as billed?If this is right then the outcome of no trial can ever be gainsaid, all appeals should be forbidden, and the jury process should be sanctified as some ineffable, inexplicable conveyance of mystical verities by means of holy procedure, to be hereafter obeyed.That is not how things work. Trials are reported, there are sequences, there are critical phases, points of sharp drama and afternoons of procedural guff. Witnesses make mistakes and can suffer from cognitive bias. Jurors switch off, or are illogical. Counsel can underperform, or focus their case on a set of issues that don’t resonate with the jury.We are entitled as citizens to know about these things. We are entitled to interrogate them. We are entitled to be satisfied about them.Above all, justice, before and after conviction, should remain transparent. If it is really true that you can’t possibly know unless you were in the jury box, then that is a profoundly unsatisfactory thing in itself.Jurors may be selected from the electoral role: they are not the electorate’s delegates. Seeing how little skin they have in the game — by definition, jurors have none — jury decisions should be as accountable to the rest of us as any are other actions of state to oversight, scrutiny and review.Shouldn’t they?This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. 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This is a follow on piece from Lucy Letby: waiver of privilege? It is mainly about waiver in a criminal context. The rules around waiver are more developed in the civil cases, since waiving privilege there is not quite as catastrophic to life, liberty and freedom, so it does happen.A document or communication is “once privileged, always privileged”. The principle that a client should be free to consult his legal advisers without fear of his communications being revealed is a fundamental condition on which the administration of justice as a whole rests. Legal professional privilege is the predominant public interest to be upheld, even where the client no longer has any recognisable interest in preserving the confidentiality or has died, or, in the case of a company, been dissolved.— Archbold on Evidence, 12-14You come at the king, you best not miss.— Omar Little, The WireUnusually, the JC made a bit of a splash when a recent piece on waiver of privilege in the Lucy Letby case caught the attention of the Double Jeopardy: Law and Policy podcast.After the usual introductory blancmange, the article settles down and looks at the case of R v Singh which seems to reverse the sacred principle that no judicial officer can come between a client and her lawyer: that all their words, notes, letters, suggestions, gestures, innuendoes and privately-communicated semaphores may forever, and for all purposes, stay private, except where the very contents of a privileged communication themselves are the issue before the court — if, for example, a defendant appeals on the grounds that she was given negligent advice.Until 2017, there were discrete and unobjectionable rules dealing with two commonly “time wastey” scenarios: firstly, were a defendant has parted ways with trial counsel and appointed new representatives for an appeal; secondly, where the defendant wishes to blame her conviction on her trial representatives doing a bad job.This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber.While they are often related, these scenarios are nonetheless conceptually distinct.The rules, in essence, are firstly, that new counsel must confirm to the court they have spoken thoroughly with outgoing counsel and fully understand the background and their strategy at the original trial — this is the rule in R v McCook — and secondly, if the defendant wishes to blame her conviction on her trial representatives’ “inadequate representation”, then she must waive legal privilege in her discussions with the trial representatives to the extent needed for the Court to determine whether the trial representatives were to blame or not. This principle comes from a case called R v Frost-Helmsing.But in 2017, those sensible rules got tangled up with the Court of Appeal’s notorious aversion to hearing fresh evidence in the case of R v Singh. There ought to be a clap of thunder, a lightning bolt and a blood-curdling scream, by the way, whenever anyone says “fresh evidence”, such is the Court’s aversion to it.Now, whenever a defendant has appointed fresh representatives, and they wish to present fresh evidence, they must submit a signed waiver of privilege before the judge will even consider whether to hear an appeal, even if there is no suggestion of negligence by the trial representatives.The text version of the rest of the article — it’s a monster — can be found here.Thanks for reading! This post is public so feel free to share it. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

In his summing up, Mr Justice Goss instructed the jury that they did not need to be sure precisely how Ms. Letby murdered the infants, as long as they were sure she did:“If you are sure that someone on the unit was deliberately harming a baby or babies you do not have to be sure of the precise harmful act or acts; in some instances there may have been more than one. To find the defendant guilty, however, you must be sure that she deliberately did some harmful act to the baby the subject of the count on the indictment and the act or acts were accompanied by the intent and, in the case of murder, were causative of death [...].”Later, he said:“In the case of each child, without necessarily having to determine the precise cause or causes of their death, and for which no natural or known cause was said to be apparent at the time, you must be sure that the act or acts of the defendant, whatever they were, caused the child’s death, in that it was more than a minimal cause. The defendant says that she did nothing inappropriate, let alone harmful to any child.”Before I go on, a nitpick. Why must lawyers torture the language so? What did it ever do to them? When the judge says to the jury:To find the defendant guilty, however, you must be sure that she deliberately did some harmful act to the baby the subject of the count on the indictment and the act or acts were accompanied by the intent and, in the case of murder, was causative of death.What he means is:To find the defendant guilty you must be sure she deliberately harmed the babies and, where charged with murder, murdered them.The courts have been at pains to “demystify” the formal legalese of the criminal justice system — it binned the clear phrase “beyond reasonable doubt” in favour of vaguer “sure” some years ago — but reforming terminology is pointless as long as practitioners still speak like Mr. Tulkinghorn. Circumlocution was a feature of Ms. Letby’s trial.Anyway.Thanks for reading! This post is public so feel free to share it.A standard directionMr Justice Goss’s direction was standard. He may have adapted it from a pre-prepared script used in similar cases. In principle, it is correct and, in certain cases, undoubtedly sensible: it helps the jury convict where, for other reasons, it does not doubt the defendant is guilty, but lacks precise detail about how she carried out the crime.After all, without a body, a court could not otherwise convict for murder.There are two parts to the direction. Mr. Justice Goss introduces them in the reverse of their logical order, which is as follows:* You must be sure the defendant deliberately harmed the babies in a way she knew was likely to kill them.* If, and only if, you are sure that, she did something intended to kill them, you need not be sure exactly what that thing was.Of course, usually one becomes sure a defendant committed a crime by identifying precisely how she did it. But if no one witnessed murder and there is no body, for example, that will not be possible. Hence the direction.There are cases where it might apply even where there is a body, but you have to be somewhat imaginative to contrive examples. With apologies to Charles Dickens, try this one:The tragic case of Nancy and BillImagine a murder trial where there is unimpeachable evidence from credible witnesses that Nancy met the following miserable end:Nancy was alone in an empty room.Bill entered with a cricket bat and a baseball bat and closed the door behind him.Bill and Nancy were overheard arguing. Nancy shrieked, “No, Bill! Please don’t hit me!”Bill replied, “You asked for it.”Several audible thuds followed. Bill then left the room, covered in blood, slammed the door and stormed off.Police discovered Nancy in the room, beaten to death. They recovered the charred remains of the bats from the fireplace.There is no doubt Bill murdered Nancy. It doesn’t matter whether he used a cricket bat, a baseball bat or some other unknown implement: she was definitely murdered, and he definitely did it. There is no other possible explanation for her death. The jury should, of course, convict.You can imagine the judge in Bill’s case directing the jury the same way Mr Justice Goss did:If you are sure Bill deliberately beat Nancy to death, you do not have to be sure of the precise instrument or instruments; there may have been more than one. To find Bill guilty, however, you must be sure that he deliberately beat Nancy somehow, intended his act and thereby caused Nancy’s death.We can see at once that this is sensible: it would be unthinkable for Bill to escape conviction simply because his jury, knowing full well he used some weapon, was unsure precisely which one.Ms. Letby is not like Bill SikesMs. Letby’s case is different. Here there is another possible explanation: the babies were all vulnerable infants in a neonatal intensive care unit. They might have collapsed without anyone trying to harm them.Absent better evidence incriminating Ms. Letby, this is without question a reasonable doubt: if these babies weren’t at elevated risk of death by natural causes, they wouldn’t have been in an intensive care unit.But Mr. Justice Goss judge put that important qualification on his direction in the second stage:you must be sure that she deliberately did some harmful act to the baby [...] accompanied by the intent and, in the case of murder, [it] was causative of death.What he did not say, but perhaps should have is,If you are not sure that the defendant deliberately harmed the babies, you need not worry precisely what that act she did. You are not sure she did an act at all. In that case, you should acquit.For, if there is an plausible innocent explanation that you cannot rule out, how can you be sure she did it? You need to rule out all possible innocent explanations. And how can you possibly rule out an open set of possibilities unless you know exactly what the defendant did?There is a circularity here.* If I am sure Ms. Letby murdered the babies, I do not need to know precisely how she did it.* In this case there is a reasonable possibility the babies died of natural causes (including unknown unknowns).* Therefore I am not sure Ms. Letby murdered the babies.* To be sure Ms. Letby murdered the babies, I must rule out natural causes.* Logically, I cannot rule out all unknown unknowns, i.e., natural causes, by elimination.* The only practical way to rule out natural causes, is for the positive evidence that Ms. Letby murdered the babies be overwhelming.* The positive evidence incriminating Ms. Letby is not overwhelming: she did not confess. The forensic evidence does not specifically implicate her. The implied correlation has been debunked.* The only positive evidence that could rule out innocent causes of death would be direct evidence establishing the precise method of murder.* Therefore, to be sure Ms. Letby murdered the babies, I do need to know precisely how she murdered the babies.It is hard to frame hypotheticals here because the sort of evidence that usually makes juries certain a defendant is guilty is direct eye-witness evidence that they committed the crime, or circumstantial evidence so closely adjacent to the crime that there is no credible inference one could draw other than that the defendant is guilty.The “Sherlock Holmes method” seemingly favoured by Dr. Evans makes for great fiction, but as it requires proving a negative — you cannot eliminate unknown unknowns by deduction — it does not work in real life. The way one disproves “unknowns” is by positively proving a “known”: a defendant with a gunshot wound to the head is most unlikely to have died of an asthma attack.If there is clear evidence of murder, it is not difficult to infer the action that caused it: a gunshot wound implies a pulled trigger.If there is not, then there must be doubt that it was that perpetrator. Bill and Nancy’s case is the unusual case justifying the direction.But that direction, therefore, ought to have been unnecessary here. It seems misplaced. It seems apt to confuse a jury doubtlessly already brain-fried by ten months of baffling technical evidence, the circumlocutions of senior barristers, and a judge’s summing up that was as long as a Tolkien novel.In Ms. Letby’s case, the victims’ “manner of collapse” did not, to the exclusion of anything else, imply malice. We know this definitively because every collapse that led to a formal medical examination, concluded — based on the best live, real-time evidence it could get — that the collapse had natural causes.The Crown must definitively displace this presumption. The only way of doing that was by showing precisely how Ms. Letby is supposed to have caused the collapses.Implausible coincidence as compelling evidenceThe direct forensics do not seem directly to implicate Ms. Letby. Could there be some meta-evidence that could do so instead? As discussed elsewhere, the main — only, really — evidence the prosecution offered that implicating Ms. Letby personally was her commonality: the seemingly implausible coincidence that she, and only she, turned up like a bad penny at every collapse for which she was charged.Once may be happenstance, twice coincidence, but by the time we get to the twenty-second occasion, we are surely past the point of even enemy action.But this is not positive evidence, but probabilistic inference. Its credibility can only be assessed by a statistical analysis, and one was not carried out. The Crown Prosecution Service nixed a police line of inquiry into exactly that question.The appealThe defence appealed the Judge’s direction to the Court of Appeal, which gave its judgment on 2 July, 2024. It was not sympathetic.Mr. Myers submitted that the jury should be directed that they could not convict the applicant of any count unless they were sure of how the baby concerned had been harmed. He argued that the counts on the indictment were specific to time and place; they were for the most part based on one or more alleged mechanisms of injury which had been the subject of detailed evidence; the case had been opened and the evidence adduced on the basis of those allegations as to the mechanism of injury; and the jury had to be sure of the requisite intention, and of causation, each of which required them to identify what had happened and when. He further argued that a direction which permitted the jury to convict without being sure of the specific harmful act or acts risked the jury wrongly convicting on the basis of the applicant’s presence alone, a risk which would be exacerbated by the anticipated direction as to cross-admissibility.The judge did not accept those submissions, although he did amend his initial draft of his proposed direction.In his submissions, on Ms. Letby’s behalf, Mr. Myers cited Angela Cannings’ case:[as] the prosecution relied on witnesses who put forward specific causes of harm and rejected other explanations suggested by the defence, the jury should have been directed to decide whether they were sure that the prosecution had proved the specific mechanism of harm which had been alleged in relation to each individual child. He further reiterates that it was necessary for the jury to be sure of the precise mechanism by which harm was caused before they could be sure of the alleged intention, and before they could safely eliminate other possible explanations for a baby’s collapse or death, such as natural causes or sub-optimal care.This is more or less exactly the argument I have set out above. Mr. Myers tied it, too, to the “unmistakeable signature” argument:... the direction given by the judge gave rise to risks that the jury may wrongly treat the applicant’s presence on the unit at a particular time as sufficient in itself to establish her guilt [...]. He makes the further point that, in the light of the judge’s direction as to cross-admissibility, the jury, having reached a guilty verdict by differing factual routes, would then have been permitted to use that verdict as support for the prosecution case on other counts.The jury might be tempted to think that Ms. Letby’s presence was all that was needed to convict: that they didn’t need to have any theory of how she committed the murders, as long as she was there.The “judge’s direction as to cross-admissibility”, is a direction along the lines of the “signature” argument, that if you are satisfied there was malice, and you are satisfied that Ms. Letby committed one murder, you can apply that evidence to infer that she committed other murders too. It is frightfully convoluted and, ultimately, illogical direction that compounds the problem with this direction, but was rendered in such opaque language that the jury is not likely have understood it, much less remembered it.The Crown’s barrister Mr. Johnson accepted that the Crown had to prove each of the legal ingredients of the offence, and cited cases in which the prosecution had done that without knowing the exact cause of murder: where no body was found, for example.Mr. Johnson asserted a clear distinction between:“… a matter which is (i) an ingredient of the offence; and (ii) a merely evidential – or ancillary – issue. It is common ground that on the latter there is no need for jury unanimity.”In our Bill and Nancy case the “ingredient” of the offence is “causing Nancy’s death”, and the evidential or ancilliary issue was “was it by cricket bat, baseball bat, or some other blunt implement?”To follow Mr Johnson’s common ground, as long as all 12 jurors were certain Bill caused Nancy’s death, it would not matter if 4 were sure he used the cricket bat, four were sure he used the baseball bat, and 4 were sure he used a truncheon concealed under his cloak. What matters is that all twelve were sure he murdered Nancy.This is not a very plausible hypothetical. In reality, the twelve may have varying strengths of view about what implement Bill used, but would be open to persuasion that he used any or all of them. It doesn’t, as the direction has it, matter, as long as he definitely used at least one.A prosecution who managed to convince different jurors, beyond reasonable doubt, that the same defendant had used positively different, mutually exclusive means of doing the same thing seems, to me, would have a bit of a philosophical problem: how can it be satisfactory for different jurors to be definitively certain about mutually exclusive accounts of the same transaction? In practice, it would never happen, of course — but, for that very reason, it is an especially absurd, and weak, reductio.The verdict, in the Court of Appeal’s view, relied on other facts and circumstances, including the “confession post-it note”, Ms. Letby’s retention of “trophies” (though they were never once described that way during the trial) andher presence at the time and place when most of the sudden collapses occurred, the fact that a number of the babies concerned suffered a catastrophic collapse only a very short time after their designated nurse had briefly left the room, and the fact that siblings suffered harm at or about the same time as each other.But none of this weak circumstantial evidence, even if taken on its face, establishes even more likely than not, let alone beyond reasonable doubt, that Ms. Letby harmed any children.The Court of Appeal was not persuaded. It found comfort, impliedly in the overwhelming probabilities of the case:Mr Myers’ submissions do not persuade us that it was necessary, before the jury could exclude those other possibilities, that they must all agree on the precise act or acts which the applicant committed. The issue for them was whether the evidence as a whole drove them to the conclusion that the applicant, by a deliberate and unlawful act or acts, had inflicted harm which caused or contributed to the baby’s collapse or death.But what was it about “the evidence as a whole”, weak as it was, that could possibly drive the jury to that conclusion beyond reasonable doubt other than the statistical unlikelihood of Ms. Letby’s constant presence?It was not necessary for the prosecution to prove the precise manner in which she had acted. To impose such a burden on the prosecution would be wrong in law: as the single judge said, it would confuse proof of the relevant fact, that harm had been deliberately caused, with the evidential route (encompassing all of the circumstantial evidence, not merely the medical evidence) by which that fact could be proved. That may be illustrated by the reflection that, taken to its logical extreme, the defence submission would appear to mean that the jury would not have been entitled to convict if – in addition to the evidence adduced by the prosecution – the applicant had given evidence admitting that she had intentionally and unlawfully killed a baby, but declined to say how precisely she had done so.But the Court’s reductio ad absurdum here does not follow. The defence submission requires that the jury is first satisfied beyond reasonable doubt that the defendant is guilty. In a case without direct evidence or a confession and with plausible innocent explanations for the allegations, it is hard to see how it could be, unless they were satisfied precisely how she did it.The “relevant fact” — a generalised, abstract legal categorisation — and the “evidential route by which that ‘fact’ could be proved” — a concrete real-world transaction which satisfies the abstract legal categorisation — may be ontologically distinct but, if only one real-world action could satisfy the abstract legal categorisation, they are the same.Here the abstract legal categorisation is “the collapses were not innocent”. In the abstract, that could generally be satisfied in an uncountable number of ways. But one (or more) out of that great infinity must be proven to the exclusion of the great infinity of competing innocent explanations. There are a very few “real-world transactions” that can achieve this: A body showing unequivocal signs of foul play. Direct, eye-witness evidence of foul play. A credible, but defiantly unspecific, confession of exactly the sort the Court of Appeal envisages in that passage. Each of these could categorically wipe out any hypothesis that the collapses were caused by any of the great infinity of innocent explanations. There were none.This is to say: to be sure the collapses were not innocent, the jury must have positive grounds for believing they were criminal that are strong enough to rule out the otherwise unlimited class of innocent explanations.Even if oddly under-specified, the defendant’s credible confession, to take the court’s example, is precisely such a positive ground. If she tells the Court that she intentionally and unlawfully murdered the victim, the jury can, from that moment, be certain. Her statement, by itself, falsifies every possible innocent explanation. If it is true, it cannot also be true that an innocent circumstance befell the victim. The jury can be sure. Part one of Mr. Justice Goss’s two-part logical test is satisfied.How the defendant did the dirty deed it has copped to is now, in Mr Johnson’s phrase, an “ancillary” detail. It is not even part of the “evidential route by which that fact could be proved”. It is simply “colour”.But the highly artificial scenario of a defendant at the same time full-bloodedly confessing, but refusing to disclose details — look, it could happen, I guess — is a unique scenario. Without it, the jury must have independent grounds for being sure that the defendant committed murder.There must be a “Bill and Nancy” scenario: where there is no plausible way the victim could have died other than by the defendant’s hand.That is not the case with Ms. Letby. The closest call seems to be the insulin immunoassay test but there are several reservations about this evidence. They do not completely rebut it, but they leave room for a good deal of doubt about it, and that is all they need to do: the immunoassays tested were explicitly labelled as not sufficiently accurate for forensic use. The immunoassay samples were not even re-tested with immunoassays, let alone being sent for more conclusive tests as was recommended. The readings they returned seemed on their face implausible, especially given that the children survived. It may be c-peptide readings in neonates tend to be lower than in adults. The “chain of custody” seems suspect: there is scope that one un-named twin was accidentally given insulin prescribed for his sibling.At this remove, no one can prove any of these doubts, but nor — without compelling direct evidence — can they be disproven. All they need to do is represent a reasonable doubt. (There is an asymmetry of outcomes in the criminal burden of proof, by the way: the more plausible innocent alternative explanations there are, however mutually exclusive they may be, the more reasonable doubt there is. At the end of the day, all definitive explanations of how a crime went down — or did not go down — are mutually exclusive. Only one can be correct. We just can’t know which. This is the great, epistemic uncertainty of the world. We can only assign probabilities.)To return to the logical premise underlying this judge’s direction:* You must be sure the defendant deliberately harmed the babies in a way she knew was likely to kill them.* If, and only if, you are sure that, she did something intended to kill them, you need not be sure exactly what that thing was.The direction ought to get stuck at 1, because the only way of being sure that the defendant deliberately harmed the babies is to know the precise act she did to harm them. Knowledge of the precise act is what justifies the jury ruling out those alternative explanations.The Court of Appeal’s judgment goes no further than that. It might be true that, in the abstract, the judge’s direction was correct as a general statement of law. But it would only come into play in certain limited circumstances. Since those circumstances did not prevail in Ms. Letby’s case the direction was, at best, irrelevant, and — especially given how it was articulated, with the important qualifying condition being left till the end — at worst potentially misleading for the jury.They may have taken from it, “Oh: the Crown doesn’t need to prove what the defendant did for me to convict her.”Discussing this with the good people of Twitter, one — Eruthmas — summed up more or less everything I have to say here as follows. This was fairly dispiriting, after all my effort — but all the same, it seems wrong to deprive you of it:“This was a case where without proof of how she killed, there was no proof THAT she killed.”—EruthmasThis Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

Take the following hypothetical scene, which describes Lucy Letby’s experience at the Countess of Chester Hospital:Internal investigationA hospital experiences a cluster of deaths and collapses materially in excess of its usual rates for such events.Staff notice a particular nurse was present during an abnormal proportion of the collapses.Concerned at the possibility of foul play, hospital management investigates the collapses, focusing on those where the nurse was present. Those where she was absent are removed from the cluster.The investigation is widened to include other unexplained collapses at which the nurse was present. Some are added to suspicious cluster.External investigationThough hospital management has not thoroughly considered alternative possibilities — that the cluster was simply “statistical noise” or that it had a different, non-malicious explanation — it presents its suspicions to the police.Police investigate the narrow question “whether there are sufficient grounds to prosecute the nurse” and not, specifically, “what else could have caused the original cluster?” Police do not interrogate the hospital’s internal investigation methodology.Instead, Police seek firstly evidence consistent with foul play — typically technical medical analysis — and secondly, given there has been foul play, evidence consistent with the nurse being behind it — this will be weak circumstantial evidence of “unusual behaviour” consistent with guilt. These two steps are markedly distinct. Notably, Police disregard behaviours “consistent with” the nurse’s innocence.Media involvementThe media pick up the story. Through repetition and hyperbole, the nurse’s identified “guilty“ behaviours are sensationalised to be ever more incriminating.“Experts” speculate on the nurse’s motivation: “God complex”, “craving attention”, “Munchausen’s by proxy”, secretive behaviour” for example. Though they frequently contradict and none were formally diagnosed before (or after) the investigation, these descriptions are taken in the round as further corroboration of the nurse’s guilt.This may sound like a carefully tailored account of Ms. Letby’s apprehension and conviction, but it is not: it describes the pattern followed in the prosecutions of Beverley Allitt, Benjamin Geen, Colin Norris, Susan Nelles, Jane Bolding, Victorino Chua, Lucia de Berk, Daniela Poggiali and dozens of other health professionals prosecuted in the western world for murder by poisoning.Thanks for reading! This post is public so feel free to share it.First find a suspect, then find a crimeNow, this is not to imply that none of these individuals committed murder nor, necessarily, that all were wrongly prosecuted — though some of them were — but rather to note that the “healthcare serial murder” scenario presents distinctive challenges uncommon in normal crime scene investigations.Normally, criminal investigations start with little doubt there’s been a crime, but a lot about who committed it. A dead body with an ice-pick in its ear and a bullet-holed playing card in its breast pocket is all but certain to have been murdered. The investigator’s main challenge is working out by whom: once identified, linking the villain to the crime tends to be straightforward.With healthcare serial murder cases, the “route to suspicion” is curiously backward. It starts with a cluster of events that could be but, all else being equal, are most likely not, criminal in nature. Assuming, nevertheless, they are criminal, investigators then hypothesise about the most likely suspect. Inevitably, their suspicion falls upon the person present at the most identified events.There may then follow an exercise in “refining” the cluster to better fit the “foul play” theory. Collapses at which the nurse was not present may be dropped — recharacterised as non-suspicious — while previously unsuspicious collapses during the nurse’s shifts may be upgraded to “suspicious” in light of her presence.The refined cluster will, by her constant presence alone, much more strongly implicate the nurse then the original one did. This is, of course, the Texas sharpshooter at work before our very eyes.With that “stronger” framework for suspicion, investigators will set about finding evidence to support their theory of foul play. This process may start before police are involved, but will carry on with great gusto once they are on the case. It will often gloss over two important steps:Firstly, if investigators put any effort at all into ruling out innocent explanations, it will be early in the process, and will be peremptory.Secondly, investigators will make little effort to link any wrongdoing directly to the suspect. The main “identification” evidence will be the nurse’s “unique opportunity”. Since, the reasoning goes, she is the only person who could have done it, little needs to be done to show that she actually did do it.Ms. Letby’s is perhaps the most pristine example. The consultants started with the plainest concession to police they had no grounds for suspecting foul play in any of the collapses, and no grounds for concern about Ms. Letby:NurseAs part of the review staffing was looked at, there was a notable high statistical relationship between a member of the nursing staff and babies deteriorating in the unit. There is no evidence, other than coincidence.[...]The nurse has been working at COCH for approximately 8 years full time, she is a Cheshire resident, and a single parent. The staff member has since placed a grievance against COCH. There has been no formal investigation of misconduct and no motive identified. There are no mental health issues known and nothing has been highlighted by occupational health. There are no management issues.Yet they still managed to move a jury from “no evidence of any crime” to “legal certainty about most of them”.Just how that happened is the topic of this post.Epistemology and the lawAquick reminder about the epistemology of the law. Where there is a dispute about what happened, any court case is beset by “epistemic” uncertainty. History is fixed. Deeds are done. What those deeds were and whether they were dirty may be as immutable as the stars but, still, certain knowledge of them is beyond our mortal grasp.A court does not and cannot know what really happened. It, and the whole of the rest of the outside world, is in a state of permanent, incurable un-knowledge about it. The best it can do is assess likelihoods.A criminal trial is a highly artificial contrivance. One way of looking at it is that it is designed to solve this exact problem — incurable epistemic uncertainty — by generating reliable probability estimates. Criminal trials cannot and do not purport to generate certainties. The process is fundamentally probabilistic.Those outraged that anyone should question the delivered verdict of a British jury should remember this: even a flawlessly-conducted trial between expert counsel examining perfectly-motivated witnesses before an enlightened jury can deliver injustice. “Beyond reasonable doubt” is an epistemic step short of certainty. The system’s reliability can itself be measured in probabilities.According to ONS data, the annual homicide rate in the UK has been a relatively stable 550 since 1970. According to University of Exeter data in that time there have been 150 false convictions. This gives a false conviction rate of just under 1%. If we take the beyond reasonable doubt probability of “95%” assessment at face value, this means the system is meeting, or exceeding, its SLA: A 95% certainty rates implies a 5% false conviction rate.A criminal trial is designed to isolate an artificially limited set of legally relevant facts and assign them probabilities as a way of assessing of what is most likely to have happened and whether that satisfied the artificial legal construct called a “crime”.That court assessments are expressed in words — “beyond reasonable doubt”, “more likely than not” — should not obscure the fact that they are probabilistic assessments. Explicitly, criminal courts convict on probabilities lower than 1. A small, but statistically significant, error rate is factored in. There is no magic to it: the criminal process shares all our human cognitive frailties.Though barristers tend to, we should not put it on a pedestal.“I wouldn’t start from here”There is an old joke, these days not politically correct, even though it articulates unassailable wisdom:A lost tourist asks a local policeman for directions to Dublin’s cathedral. The policeman scratches his chin and says, “Well, if I were you, I wouldn’t start from here.”The soundness of your conclusion depends on the plausibility of your premises. All else being equal, start with the most likely explanation, and stick with it until something rules it out. If you are curious about a cluster of collapses, don’t start with murder.Patients do unexpectedly collapse at every hospital every year. Nurses don’t, very often, murder patients. Starting with a cluster of unexpected collapses and proceeding directly to a murder investigation is a bit like hearing hoofbeats and looking for a zebra.If that is your frame — and in healthcare serial murder cases, invariably it is — you are at grave risk of bad confirmation bias.Good and bad confirmation biasConfirmation biaskɒnfəˈmeɪʃᵊn ˈbaɪəs (n.)The tendency to search for, interpret, and recall information that confirms a pre-existing belief, preferring information that supports that belief, ignoring information that contradicts it, interpreting ambiguous information to be consistent with the belief, and more readily recalling information that confirms the belief than that which challenges it.Not all confirmation bias is bad. In fact, it is one of homo sapiens’ principle reasoning strategies. Being instinctive pattern-matchers we owe our sustained success in the evolutionary lottery to our ability quickly and instinctively to observe, orient, decide and act. We survey and assess and react to a situation in real-time based on our experience, usually before our deliberative function has made it out of bed. In common scenarios it works well. When we tread on the pavement, we trust it will bear our weight. When we flip the switch, we are confident the kettle will boil.When we hear hoofbeats, we assume horses.We thereby practice a kind of unwitting Bayesian heuristic. I have walked along the footpath outside my house thousands of times. It has always taken my not inconsiderable weight. While there is a non-zero chance that, this morning, a sinkhole could open up and swallow me, my experience tells me it will not. This is a form of confirmation bias. On regular days, it is highly unlikely to let me down.Our cognitive machine is well-oiled, fast and, mostly, reliable. Occasionally, it lets us down: usually in unusual scenarios, edge cases, and where our emotions are engaged. We are curiously vulnerable to deception by malign interlopers at the periphery. But still, when it comes to healthcare professionals, there are few “malign interlopers”. The credentialisation process in the healthcare industry is, in part, designed to weed them out.In any case, quick, low-intensity decision making — heuristics in place of careful analysis in familiar cases — is a core survival tactic. It is skewed, however, to err in favour of self-preservation: the man who mistakes a rock for a bear survives. The one who mistakes a bear for a rock does not. When in doubt, to hell with the other guy.Our doubts sit on a continuum between normalcy and oddness. Most of them are at the oddness end. There are many “samey” days, a few unusual ones, and tiny number that are totally weird. If you aren’t sure what kind of day it is, assume it’s a samey one. We are most unlikely to misread “samey” days. It is less likely to matter if we do. It is weird days that catch us out.The surprising risk of false positivesJust how likely are false positives? Well, here is a fun thought experiment: let’s compare the base rate probability of a false conviction for murder with the probability a given nurse actually is a murderer.When you combine these probabilities it produces a rather surprising result.For the false conviction base rate let’s take our 1% estimate of the miscarriage of justice rate and give the courts the benefit of an order of magnitude of doubt. We will divide that error rate by ten. Say only one in one thousand murder convictions are wrongful, giving a wrongful conviction rate of 0.1%.Now let’s estimate, roughly, the prevalence of murderers in the nursing community. We can do this by reference to healthcare serial murder convictions over the last 50 years across America and Western Europe. In that time, there has been a surprisingly steady rate of about 1 conviction per year. If we say there were, at a conservative estimate, roughly 5 million medical professionals in North America and Europe at any time over that period, the going “rate” of murderers among medical professionals runs at about 1 in five million. That is pleasingly rare.So:1 in 1,000 miscarriages of justice1 in 5,000,000 healthcare serial murderersBase rate neglect: why it is overwhelmingly likely a conviction is falseNow: if we happened to pull that one-in-five-million “true positive” killer nurse out of a hat and put her on trial, with a 0.1% false conviction rate, we could be extremely confident she would be convicted. Happy days.But she is but a single needle in a haystack of 4,999,999 innocent nurses. What if, by accident, we pulled an innocent nurse out of our hat and put her on trial instead? What would her chance of acquittal be?Also, 99.9%. So, also, happy days!But hold on. There is something — well, someone — missing: we have our one “true positive” murderer — that’s great — and we also have the 99.9% “true negative” innocents — also, great — but 99.9% of 5 million is only 4,995,000.Where are the other 4,999 innocent nurses?Well, this is awkward: they are in prison.The corollary of that healthy 99.9% accuracy rate is that rate for every one actual murderer you convict, you would expect to convict 4,999 innocent nurses. That is a low strike rate. It means if we try a nurse at random, she is overwhelmingly likely to be innocent, and (a bit less) overwhelmingly likely to be acquitted.But if we try a nurse at random and she is convicted, she is overwhelmingly likely to be innocent.But we don’t just try nurses at random“But hold on, JC: this all presumes we put nurses on trial for murder at random. We don’t: we only try nurses we are pretty sure, on good grounds, will be found guilty. Aren’t these bamboozling statistics you are laying on us just a cheap parlour trick?”If we put nurses on trial only when we first had solid direct evidence of murder — eyewitnesses, CCTV footage, freely-given confessions and so on — this would be true. But we don’t. The nature of “healthcare serial murder” is that, usually, at first there is no direct evidence. The suspicion of foul play, at first, arises from a given nurse’s opportunity.If there is a statistical parlour trick going on here, that is it: we are relying on “implausible coincidence” rather than “compelling evidence of criminal behaviour” to convict our nurse. We don’t have any better grounds for believing this nurse to be a murderer than any other nurse. Almost always, the nurse just happened to be there. That’s the incriminating evidence. There is nothing to differentiate her, qualitatively, from the general population of nurses who do not commit murder.When it comes to healthcare serial murder investigations, it seems, we do just try nurses at random.How confirmation bias worksA prosecutor must prove, beyond reasonable doubt, that the cluster not only was caused by malice, but by the malice of a single nurse, since the prospect of multiple independent murderers in one hospital is unthinkable even to those in the grip of prosecutor’s tunnel vision.This forces an odd dilemma onto the prosecution. If we step through it we can get a sense of how a highly improbable possibility morphs into an apparent certainty, though a series of unconscious, invalid, cognitive manoeuvres.* On day one, there is no direct, or even circumstantial, evidence of murder. The prosecution’s suspicion that there might be murder arises from:* an unusual cluster of deaths and* the presence, at many of those deaths — not yet all of them: we’ll get to that — of one nurse.* The suspicion of murder emerges from the entirety of the cluster, and not out of any single case.* There is an important preliminary point in the reasoning here:* If it is a “medical” murder in a secure hospital environment — Spartan if — the list of possible suspects is limited to those with the skills, apparatus and access to carry out the murder.* That means, if it is murder — Spartan if — the murderer is almost certain to be an on-duty medical professional.* It will be tempting to hear the second part of that sentence — “the murderer is almost certain to be an on-duty medical professional” — while ignoring the first part, upon which it is entirely conditional: “if it is murder”. This would be a grave mistake: as we have seen, murder by a medical professional in an intensive care unit is very, very unlikely.* There’s second subtle point here, too. Given the lack of strong social ties between nurse and a patient, the usual psychological motivations for “one-off” murders — jealousy, grudge, age-old familial resentment — are unlikely. A nurse who murders is likely to be a sociopath. Sociopathic motivations are enduring: they are unlikely to stop at one victim. Conversely, someone who does “stop at one victim” is not likely to be a sociopath.* Murderers who are not sociopaths will generally be in social networks with their victim: this is another way of saying “normally adjusted people don’t randomly murder strangers”. Nurses tend not to be in social networks with their patients — especially when those patients are infants. So if the murderer is not a sociopath, it is most unlikely to be a nurse. So we have this weird world where a nurse is either a serial murderer, or not a murderer at all. Since we suspect the nurse, we are obliged to seek out evidence of multiple offences.* Back to our cluster. Besides opportunity, we don’t, yet, have any better grounds to suspect our nurse than any other nurse on the ward. We had better find some. Investigators systematically search the record for information to corroborate the suspicion, discarding information that tends to contradict it. The risk of confirmation bias arises.* It would be better to seek evidence that there was no murder, as that is more likely. Without a pre-existing theory we are less prone to confirmation bias here: it could be, literally, anything. But looking for non-apparent reasons not to prosecute is not generally what detectives do.* Instead, the police will engage new experts to sift through the records looking for evidence of murder that was previously missed. They will inspect x-rays, analyse immunoassay test results, re-examine post mortems, study internet search histories, interrogate ex-boyfriends and dig up gardens. Anything consistent with murder is fitted into the frame. Anything else is set aside.* Inevitably, plenty of “circumstantial evidence” like this will turn up. Much of it will be ambiguous, probative of little, and highly prejudicial. The “medical evidence” arising from re-evaluated medical records will not personally incriminate the suspect but will instead be presented as evidence of criminality in the abstract: even though none of the duty doctors or pathologists detected foul play at the time, prosecution experts will be categorical, months after the fact, that there has been foul play and the records prove it. The original doctors and pathologists, who made the records, will not be called as witnesses.* The tacit inference will be drawn that if any of the collapses are murder, some or all of the others are likely to be murder too, since such a sociopath would not be able to stop herself. There is a circularity here, though, because by the same logic a lack of other attacks would tend to imply that there was not a sociopathic nurse on the loose.* In light of this re-evaluation the original cluster is revised, filtered, augmented and reassembled as a charge sheet. It will now much more clearly implicate the suspect: though she wasn’t present at all the events in the original cluster, she was present at every one of the deaths as now charged.* Though there is still little evidence directly incriminating our suspect for any offence, by logical loop there are grounds to presume she committed all of them. This is a subtle, unjustified, logical shift.* Remember our conditional probability above: “in the highly unlikely event of a murder, the murderer is almost certainly an on-duty medical professional.”* The focus now switches to supporting the inference there has been foul play by someone it need not incriminate the suspect.* In at least one case — it only needs to be one case — there will be plausible — but not definitive — grounds for that belief. The defendant may herself acquiesce in the view that “someone administered poison”, as Ms. Letby did in cross-examination.* With the presumption there has been a murder, the prosecution seems to have hurdled that tricky conditional probability. The weak sentence: “in the highly unlikely event of a murder, the murderer is almost certainly an on-duty medical professional” has turned into a very strong one: “There is a murderer, so it is almost certainly an on-duty medical professional”.* The only question now is who.* Of the thirty odd medical professionals who could have been on duty, only one, the suspect, had the opportunity for each case. It does not matter that she does not match the behavioural profile of a serial killer: we have our suspect. It literally cannot have been anyone else.* Two further subtle shifts in our reasoning have happened:* We are now sure there is a serial murderer on the ward, so if there are any cases of foul play they are highly likely to be perpetrated by her. After all, the chance of their being two murderers on the ward operating independently is vanishingly remote.* Without a known murderer on the ward, the chance a given collapse was murder is very low. But where there is a confirmed serial murderer operating in a ward, the chance a given collapse is a murder is much, much higher. The explanation that the suspect — whom we have deduced is a sociopath — murdered all of them — is suddenly very plausible.And there, in a nutshell, is the reasoning, with confirmation bias, that gets you from “there is no evidence of murder whatsoever” to “the only logical explanation is that the nurse is a serial murderer, and she killed all of them”.ConclusionIf you start with a relatively unlikely scenario and do not systematically gather evidence supporting more likely explanations, instead collecting anything, however tendentious, that fits your theory, you are at high risk of “bad” confirmation bias.The conditions for a well-intended, but all the same wrongful healthcare serial murder prosecution are the same ones that propel catastrophes of other kinds with which we are wearily familiar: financial crashes, air crashes, reactor meltdowns.They are what Charles Perrow would call “normal accidents”: they do not depend on malice aforethought but are baked into our institutions. The system by its normal operation is fated to generate these outcomes every now and then. It will produce conditions that will lead to conviction of nurses for murder whether they are guilty or not.When there are no witnesses, confessions, or clear motives the most statistically likely explanation is that confirmation bias has manufactured a case against an innocent person.This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber.See also* Confirmation bias* Texas sharpshooter* Lucy Letby: statisticsReferences This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

A leopard goes to the doctor.“Doc,” he says, “You gotta help me. Whenever I look at my wife, I see spots.”The doctor looks at him for a minute and says, “Well, what do you expect? You’re a leopard.”“I know that, Doc. But I’m married to a zebra.”Healthcare serial murder enquiries are unusual in that they generally start without specific evidence of wrongdoing as such. Suspicion generally arises from an unusually large cluster of unexpected deaths. From there, prosecutors work backwards towards a perpetrator.Their job is made harder by two inconvenient facts: firstly, hospitals generally, and intensive care units specifically, are places where “unexpected deaths” are a regrettable part of a normal operating environment. There is a “going rate” of unexpected collapse, and a “suspect cluster” is simply one that exceeds that going rate, usually not by much: a standard deviation or two above the hospital’s average. The elevated rate might be what you’d expect once in ten years, say, or fifty — but not one in a million. According to Professor Sir David Spiegelhalter’s evidence before the the Thirlwall Inquiry, the increase in deaths at the Countess of Chester Hospital’s neonatal unit in 2015 would be within the expected range for hospitals across the UK in any year:“If we assume an underlying rate of 3 neonatal deaths per year, then the probability of getting 8 or more deaths in 2015 is 0.02. This would generally be considered as constituting an “alert” signal. Again, to put this in perspective, we would expect around 3 such signals each year in the UK, just by chance alone.”Secondly, “malicious nurses furtively murdering patients” is a one-in-a-million sort of thing. You would not expect to see it “every so often” in a given ICU.All other things being equal, you would take the “one in fifty” option over the “one in a million” option. From a starting point of there being “an unusual cluster of deaths”, there is a quite likely explanation — it’s just one of those things — and a highly unlikely one — there’s a serial murderer in the ward — and no evidence, as yet, to tell us which way to lean. But as the saying has it: when you hear hoofbeats, think horses, not zebras. At least, until you see some stripes.A prosecution intent on proving murder will need “posterior evidence” to support its hunch and rebut the far more likely explanation that the cluster is just “one of those things”. Investigators must therefore scratch around looking for secondary indicators of foul play that were not picked up at the time of the deaths and, if they find any, a plausible suspect having both the opportunity and disposition to murder.The first question — “was it murder?” — can be addressed by technical medical evidence. That is not the topic of this post.This post is about the second question: “given that it was murder, whodunnit?” Here, generally, you need solid “identification evidence” incriminating a specific person. Eyewitnesses. Fingerprints. Confessions. That kind of thing.The problem with healthcare serial murder cases is that they start and often end without compelling identification evidence. Prosecutors are often obliged to resort to unusual things the suspect did, or said, that do not specifically indicate that she committed a crime, but are more broadly “consistent with” it. This is a bit of a recipe for confirmation bias.In the 1970s, the FBI’s legendary Behavioural Science Unit learned how subtle behavioural patterns could lead them to notorious serial killers. Would their techniques apply, or be any use, in a classic healthcare serial murder case?When the lambs stopped screamingLecter: Oh, Agent Starling. You think you can dissect me with this blunt little tool?Starling: No! I thought with your knowledge —Lecter: You’re so ambitious, aren’t you.—Silence of the Lambs (1991)In 1972, Howard Teten and Patrick Mullany established the FBI’s Behavioural Science Unit in Quantico, Virginia. You may remember it form the opening scenes of Silence of the Lambs. The FBI had long recognised that certain types of violent crime — “serial” ones, particularly — pose unique challenges to traditional policing methods. Serial killers murder in the shadows. They tend not to leave living witnesses, nor much in the way of physical evidence behind them.By contrast, most normal violent crime happens between people who know each other and are embedded in stable, stationary, long-established social networks. When violence breaks out there tend to be many witnesses, lots of evidence, and only a few plausible suspects. Second-order psychological inference to work out who did what is rarely needed.Serial offenders are different: they tend to be antisocial, itinerant, they target strangers, and those who are any good at it soon develop ways of avoiding detection. But they may still give themselves away by their habits and idiosyncrasies, predictors for which may be inferred from crime scenes and improbable commonalities between victims. The FBI developed behavioural profiling techniques designed to point to patterns not immediately obvious to your regular cop on the beat.Hence, the premise of a “behavioural checklist”: a range of traits which, when found in unique combination, operate as a strong predictor that an individual is predisposed to behaving in a highly unusual, uniquely antisocial way.Focus on individuals like this and you have far a better chance of finding your man.So was born the legend of the “mindhunters”: the FBI profiler brilliantly decoding the machinations of an malevolent evil genius, tracking him to his hidden lair using just his inadvertent habits and idiosyncratic behaviours. It is a beguiling, but somewhat romantic, image. Real-life “hits” from behavioural profiling are not always as sophisticated as Buffalo Bill’s dressmaking connection in Silence of the Lambs. They tend to involve relatively straightforward patterns that require some expertise to see, but are still not especially esoteric.Regular serial killers versus healthcare serial killersBeing more prosaic, “regular” serial killer investigations have particular features that lend themselves to behavioural profiling:Serial murder conundrumsLikelihood it was murder: certain.Method of murder: certain.Common perpetrator: certain.Direct evidence: none.Perpetrator identity: unknown.But mainly: you have no clue who the murderer is. What you do know, for sure, is that there has been a series of murders. You’re pretty sure they are linked: there is a specific modus operandi, and freaky features that make a coincidence highly improbable.This part of your case — were they all murders by the same individual — is not really in doubt: the corpses all have bullet-holed playing cards in their breast pocket and an ice pick in the ear. They were definitely murdered by the same guy.The question is, rather, who is that guy? A behavioural profiler asks, “What are the characteristics we would expect in a person who would commit this kind of crime?”Profiling, thus, works forward from probable patterns in certain behaviour to predict what sort of person the perpetrator will be. It narrows down who you are looking for. Once you find a suspect with the predicted characteristics, it then becomes a question of finding hard evidence to tie him to the crimes.Importantly, you develop your theory before you settle on a suspect. You use these characteristics not to verify suspects, but to weed them out. The risk of confirmation bias is therefore low.If you find a suspect who fits the profile, you must then look for hard evidence that definitively connects that suspect to the crimes — ballistics, trophies, incriminating possessions like ice picks and decks of bullet-holed playing cards — things that an innocent person is highly unlikely to have. You don’t rely on the profiling exercise itself to prove anything in court. You probably don’t even mention it. It was a preliminary filtering tool in the investigation, not a conviction technique itself.Interesting side note here, quickly: much is made in healthcare serial killer cases of the defendant’s sophistication in avoiding detection, covering her tracks and disposing of evidence: in this regard, it is assumed, healthcare serial murderers are like real serial murderers. But real serial murderers are not like this. When they are finally identified — with or without the help of behavioural profiling — they tend to be found with lots of incriminating evidence of their crimes: trophies, weapons, body parts and so on. The challenge is finding the murderer, rather than proving what he did when you do find him.Anyway, all of the above applies to regular serial murderers. Healthcare serial murderers — like killer nurses — are a different ball of wax. They don’t lend themselves to behavioural profiling:Healthcare serial murder conundrumsLikelihood it was murder: not certain.Method of murder: not certain.Common perpetrator: not certain.Direct evidence: none.Perpetrator identity: Known and already central to the investigation.Here the main thing behavioural profiling is useful for — finding a likely suspect — is already done. There is no need to scour a large, widely distributed, poorly documented and inchoate group itinerant individuals: suspicion starts and finishes with statistical clustering of deaths in a single facility staffed by a small number of people. If it is murder, the potential culprits are few and already known. Usually there is only one: the nurse with the highest correlation of shifts to collapses naturally fills the frame. Who else could it realistically be?But note: the hard question to be answered here is not “whodunnit” but was it even a murder? The suspect’s behavioural traits won’t help with that.Or will they?Behavioural profiling to backfill identification evidenceSeeing as there is no direct evidence of her doing anything, behavioural traits seem to make up a large part of the identification evidence against Lucy Letby. Seemingly innocuous behaviour like retaining handover sheets or making Facebook searches, while plainly not direct evidence of wrongdoing, are presented as the sorts of things a murderer would do. I wondered: are there others? Could we look at similar nurse serial murder cases and identify other behaviours that might mark Ms. Letby out as an unusually likely candidate? There must be something that disposes a small handful of healthcare professionals to murder vulnerable patients, when millions of common or garden nurses plainly don’t?Ever the have-a-go hero, I thought I would try it out. I might not be Silence of the Lambs’ Agent Clarice Starling, but I could at least be space-cadet Olive Budgie.I set about compiling some data from public sources — Wikipedia, Fandom’s Serial Killer Database, the FBI Vault and so on — about healthcare serial murderers to see what they are generally like. Do they have a type? Are they likely to have a history of criminal offending? Psychiatric illness? A motive? What age, sex, and marital status do they tend to be? What are their popular murder methods? Do they confess, before or after conviction?Across North America and Western Europe, I found 42 nurse serial murder convictions since 1970. That is not many. There are a few more women than men — though given the 85% female skew in the profession that still suggests a significant predominance of males. Most murder elderly or adult patients though, of the 5 convicted of murdering infants, all were female.Beyond that, information about them is thin.They are, however, unusually likely to be wrongfully convicted: more than a fifth of the 42 convictions have been overturned or are subject to outstanding formal challenge.So that is the first problem: the sample is small and, apparently, prone to error. It is likely to include known unknowns — people who aren’t healthcare serial murderers, but have been convicted of it anyway — and to omit unknown unknowns — people who are healthcare serial murderers, but haven’t been caught. There is significant “epistemic uncertainty”, in other words: we don’t know what we don’t know about healthcare serial murderers.So the behavioural traits we might derive from this list are somewhat qualified.The more I learned about base rate neglect, confirmation bias and prosecutor’s tunnel vision the more this amateur criminal profiling seemed a waste of time, so I retired space cadet Budgie. But kept my spreadsheet and resolved to see if I could find studies by better qualified people who know that they are doing.Soon enough, I did.Dr. David Wilson, emeritus professor of criminology at Birmingham City University is well-known in the serial killer field. He has written several books on the subject and intervened in a number of high profile cases, notably Lucy Letby’s. With his bright blue eyes and close-cropped silver beard he has quite the face for TV, in the same way I have one for radio and a voice for semaphore.His frequent Letby soundbites have been somewhat ambivalent — but in the main, he’s in the guilty camp. This is interesting: he is, apparently, a rare expert with no personal interest, who is prepared to support the prosecution.He’s also written about healthcare serial killer profiling. Notably, with fellow BCU Professor Elizabeth Yardley, in 2014 he published In Search of the “Angels of Death”: Conceptualising the Contemporary Nurse Healthcare Serial Killer — I didn’t realise they had changed since the olden days — a paper aiming to:“establish insights into this particular subcategory of healthcare serial killer ... [and] ... test the usefulness of an existing checklist of behaviours among this group of serial murderers.”The paper draws heavily on American criminologist Dr. Katherine Ramsland’s 2007 book Inside the Mind of Healthcare Serial Killers: Why they Kill. In her book, Professor Ramsland sets out 22 common healthcare serial murderer “behaviours”:1. Moves from one hospital to another2. Secretive/difficult personal relationships3. History of mental instability/depression4. Predicts when someone will die5. Makes odd comments/claims to be “jinxed”6. Likes to talk about death/odd behaviours when someone dies7. Higher incidences of death on his/her shift8. Seems inordinately enthused about his/her skills9. Makes inconsistent statements when challenged about deaths10. Prefers nightshifts—fewer colleagues about11. Associated with incidents at other hospitals12. Been involved with other criminal activities13. Makes colleagues anxious/suspicious14. Craves attention15. Tries to prevent others checking on his/her patients16. Hangs around during investigations of deaths17. In possession of drugs etc. at home/in locker18. Lied about personal information19. In possession of books about poison/serial murder20. Has had disciplinary problems21. Appears to have a personality disorder22. Has a substance abuse problemHmmm.Professor Ramsland is an engaging writer and, by all accounts, an experienced criminologist. But while, intuitively, many of these traits seem plausible, few bear close scrutiny. She offers little by way of explanation or amplification about how she arrived at them, or why these, and not other traits, are germane. Nor does she say how they should be interpreted or applied.Firstly, they are notably vague. If you’re hunting serial murderers by reference only to their behaviour, you would want criteria a little more hard-edged and categorical than this. What counts as “secretive”? Does “mental instability” include moodiness? What does being “associated with incidents at other hospitals” involve?Secondly, some flags contradict others. “Craving attention” is a red flag, but so is “being secretive”. “Avoiding colleagues and working night-shifts” counts, but so does being “inordinately enthusiastic”, “hanging around the investigation” and “getting in early and staying after knock-off”.Thirdly, some flags duplicate others: “moving around a lot” and “being involved in incidents at multiple hospitals” cross over, as do “predicting when someone will die”, “joking about killing” and “talking about death”.Fourthly, the flags are not “risk weighted”: “owning a book about serial murder” — I’ve got tons of those — carries the same weight as “being found in possession of unauthorised poisons”.Fifthly, one trait — “higher incidences of death on shift” — isn’t a behavioural trait at all. It is simply being at work when you are required to be. It has nothing to do with a suspect’s behaviour as such. And failing to have this trait is not just an absent check-mark from a long list of optional traits: it is a stone cold alibi. Surprise, surprise, this is, by a distance, the most prevalent trait.Sixthly, not all flags unambiguously indicate misbehaviour: you would expect your very best nurses to be “enthusiastic about their skills”, to arrive early, stay late and be prepared to work night shifts.Lastly, many of the flags fit a wide range of behaviours, including ones you would expect from any nurse, and which would be far more probable, alternative explanations than “probable serial murderer”.I could go on.And just as troubling as the dubious flags on the checklist are the obvious ones that are missing. For example, there is no “suspect was witnessed murdering patients,” nor “suspect was found with a murder weapon,” nor “suspect has a cogent motive,” nor “suspect made an unambiguous confession”.This may seem trite, but bear in mind over half of the 42 healthcare serial murderers admitted their crimes.Behavioural profiling was invented to identify unknown criminals. It is a detection tool: it helps you hunt through a haystack of innocent passers by to find a villainous needle. Once you have your needle, its utility quickly dwindles. There tends to be plenty of corroborating evidence — DNA matches, fingerprints, ballistics and so on — linking an actual culprit to his crimes. If there isn’t, he is not very likely to be the culprit. It is that corroborating hard evidence that secures the conviction, not behavioural typing. This ought to be equally true of healthcare serial murderers.Matching “observed traits” to already convicted healthcare serial murderers, therefore, is a bit of a rum business. But this is what Professor Wilson proposes. He applies the Ramsland checklist to 16 “confirmed” serial killer nurses convicted of at least two murders between 1977 and 2009 in hospitals in North America and Europe:Charles Cullen, Kimberley Saenz, Kristen Gilbert, Robert Rubane Diaz, Sonia Caleffi, Beverley Allitt, Cecile Bombeek, Vickie Dawn Jackson, Aino Nykopp-Koski, Orville Lynn Majors, Benjamin Geen, Petr Zalenka, Christine Malevre, Irene Becker, Stephan Letter, and Colin Norris.Dr. Wilson’s cohort scored a median of just 6 out of 22 of Ramsland’s red flags — five, if you exclude the non-behavioural “higher incidences of death on shift”.This is disappointingly low. Given how vague and innocuous many of the flags are, you would expect a stronger signal to emerge from the noise than that. It prompts a question: how would a “control group” of randomly chosen “normal” healthcare professionals score?Oddly, there isn’t one. This seems quite an oversight, especially where the traits are so vague and the targeted behaviour so unlikely. I have friends who work at hospitals who would score higher than six on the Ramsland scale. I don’t think any of them are serial murderers. I scored six myself, and I don’t even work in healthcare.It is hard to believe that six of these “red flags” would mark anyone out as especially unusual, let alone a one-in-a-million serial killer.Speaking of which, there is one other candidate we could apply the “Ramsland checklist” to: Lucy Letby. After two trials, multiple convictions and a decade in the public eye, there is a lot of her recorded behaviour available for convenient retrospective pattern matching. How would she get on?Well, apart from “being on shift a lot,” which is not a behavioural trait at all, you could argue none of these traits squarely describe her behaviour. The one unusual thing is her failure to fit these any of these traits. Given how vague they are, it should be easy to confabulate some red flags. But have a go: it is not.So what does Professor Wilson make of all this, then? Has he ever brought his “blunt little tool” to bear on the Letby case?After a fashion he has. In a recent piece for the Observer he agreed: she does not score high on the Ramsland checklist. Does this give him grounds for doubt?Apparently not.She simply did not display the “red flags” we have come to associate with nurses who kill within hospital settings [...].Yes, there were spikes of deaths that corresponded with her shifts, but hospitals are places where people with severe health issues are located and sadly some of those patients will die. A spike in a number of deaths on a unit or a ward can simply be a random occurrence and does not have to be an indication that a serial killer is active.We now know that what was happening in the neonatal unit in Chester was not random but was indeed the work of a murderer.So why did she do it?We might never be able to answer this question definitively, but like many of those nurses who have been convicted in the past 50 years there was probably a “hero complex” at work – a desire to be the centre of everyone’s attention; a toxic narcissism that demanded that they should have power and control, which they might have felt had been denied to them in other aspects of their lives. And what better way of demonstrating that power than deciding who should live and who should die?“Toxic narcissism”? “Hero complex”? Where on Earth did these come from? What evidence is there that Ms. Letby suffered anything like this?Rather than concluding that, in failing to display any of the behavioural traits he has identified for healthcare serial murderers, Lucy Letby may well be a false positive, Professor Wilson doubles down. Remarkably citing a refusal to explain her motive — also not on the Ramsland checklist! — Professor Wilson compares Ms. Letby to Harold Shipman:“Like most of the serial killers I have worked with and studied, Letby has been silent about what might have driven her to kill. In that respect she is like our worst British serial killer, Dr. Harold Shipman, who also maintained his innocence and refused to accept any responsibility for the deaths of at least 215 of his often elderly female patients.”Now: besides people like Harold Shipman, one other group tends to remain silent about their motivation for serial murder, of course: people who have not committed it.Confirmation bias ahoyAs the “serial offender” theory develops around a suspect, using “behavioural profiling” to work backward from the suspect to a crime carries an unusually high risk of circular reasoning: “this cluster of deaths look suspicious because of the constant presence of the suspect, and the suspect looks suspicious because of the cluster of deaths”. With 22 criteria as woolly as this, you could convict almost anyone unlucky enough to fall victim to statistical correlation.The uncomfortable reality about behavioural profiling in a healthcare environment is that if the prosecution needs to rely on behavioural profiling to get home, the risk of miscarriage of justice is already elevated. These cases are necessarily the hard ones: all the obvious markers of criminality and guilt are missing. There is already good reason to doubt a serial murderer is at work. If you are this far down the barrel, it might be time to put down the scraper and return to back to baseline probabilities. A statistical cluster is far more probable than serial murder.Remember, the baseline chance, all other things being equal, that a given nurse is a serial murderer is something like one in a million. Cases with no hard evidence to improve those odds are exactly the ones most likely to yield false positives. “False positive,” in this case, is a statistical term for “miscarriage of justice”.When you hear hoofbeats think horses, not zebras.This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

In his book The Black Swan, Nassim Nicholas Taleb presents the “ludic fallacy”: the mistake of applying unvarnished theoretical probabilities to real-world scenarios.Thanks for reading! This post is public so feel free to share it.Here is his example:You have a fair coin which, on the last 99 flips, had come up “heads”. Assuming it is a fair coin, what is the probability of it coming up “heads” on the 100th flip?Professor of statistics: Easy: 50%.Professional gambler: Come on, chump, it is 100%. What are the odds of it being a fair coin?We are looking at a highly unusual outcome. The odds of getting it with a fair coin are something like a googol to one against.That means this did not happen by chance. We can rule out the “null hypothesis”, therefore. It can’t be a truly random event: either the coin is loaded, or the flipper is somehow rigging the game.This is an effective logical argument:If:The coin is fair, andThe flipping method is fair, thenThe coin will not land heads 100 times in a row.Therefore, if the coin does land heads 100 times in a row, then either:The coin is not fair, orThe flipping method is not fair.So, we can try to get to the bottom of this.We can ask to inspect the coin. We can test it out for ourselves. If, on a thorough inspection: its weight, shape, balance, density, magnetism and so on seem fair, and if we flip it a few times for ourselves and it yields expected something like the expected 50/50 outcome, we can rule out the coin as the problem.We can ask to inspect the flipping process. We will need to be wary: an experienced hustler may be skilled at conjury. She may engineer “heads” each time through misdirection and sleight of hand. Especially if the flipping happens “off-stage”. If we can’t see the coin being flipped, we don’t know how it may have been edited or fixed to omit all the “tails” outcomes, or force the heads result.In any case, if we are not allowed to inspect the coin, or we are not allowed to observe the flipping method, alarms should sound immediately. This is what a conjurer would do. We should not let ourselves be misdirected here.Ludic fallacy appliedWe have the potential for a “ludic fallacy” in Ms. Letby’s case. We know the probability of a nurse being rostered on for a given shift. Depending on how hard she works, it is between one-in-five and one-in-three. Here, there were 25 “events” — collapses for which she was charged. She was on duty for all of them.The chances of the same nurse being present at 25 collapses in a row is a bit like flipping 100 heads in a row: the odds against it are not quite a googol to one, but they are still so vanishingly small — in the billions to one against — as to be impossible.So we can reframe our logical argument:If:Ms. Letby is innocent, andThe sampling method for the collapses is fair, thenMs. Letby will not be on duty for 25 collapses in a row.Therefore, if Ms. Letby was on duty for 25 collapses in a row, then either:She is not innocent, orThe sampling method for the collapses was not fair.The “null hypothesis” — that the collapses were caused by unrelated natural causes and Ms. Letby’s presence was a pure coincidence — is off the table.We have two things to consider: firstly, what are the “base rate” probabilities for these alternative explanations, and secondly, what evidence do we have to support the alternative explanations that might change those?Base ratesWhat is more likely? That someone, perhaps inadvertently, cherry-picked some statistics, or that a nurse tried to murder 25 premature infants?I don’t have hard data, but I hope you won’t find the suggestion that people being a bit casual with information is a bit more likely than nurse serial murderer, if you had to choose.Here, we do have to choose. We should be prepared to change our minds if the evidence requires it, but until we have a good reason, we should assume an unusual coincidence of collapses is more likely to be sampling bias than serial murder. Because, all else being equal, sampling bias is common, and serial murder isn’t.So is all else equal? There are things we can check.We can observe the nurse: her activities, her logs, hospital monitor outputs, swipe card data, recollections of other nurses, her behaviour, her social media, her apparent psychiatric state — is there anything that suggests malice? Did anyone see her attack an infant? Did she stockpile insulin? Was she spotted fiddling with feedbags? Did she Google “venous air embolus” or “killing an infant with milk”?We can also inspect the collapses. Were these patients unusually susceptible to collapse? How, generally, was the hospital performing? Were there other collapses? Were there other deaths? How thorough was the process of going through the hospital records over the 15-month suspect period to find other suspicious episodes? Have any collapses been ruled out? Can we have a look at those?And we can inspect the charge selection process. There ought to be a lot of data about that. Police, CPS and the hospital will all have copious records of their discussions, conversations and what investigations they took. There will be post-mortems and tests. We can see how the suspicion arose, how the suspicious events were tested, what has been filtered out and on what criteria.In this case, the “coin” is Ms. Letby. The “master magician” flipping it is the Crown Prosecution Service and its beautiful assistant, the Cheshire Police. How much information do we have about each, and what does it tell us?The nurseThe nurse has been working at COCH for approximately 8 years full time, she is a Cheshire resident, and a single parent. The staff member has since placed a grievance against COCH. There has been no formal investigation of misconduct and no motive identified. There are no mental health issues known and nothing has been highlighted by occupational health. There are no management issues.If a coin is loaded, you can often tell immediately. You do not always need to flip it to know. It will be misshapen, shaved, magnetised or counterweighted. At the limit, you can flip it for yourself and see how it performs. The key is to be able to freely and fully inspect it.If a nurse is repeatedly murdering patients in an intensive care unit, likewise, you should be able to tell. You should not need to look at a roster of attendance to work this out. The key is to be able to freely, fully inspect her behaviour.So, have we had an opportunity to freely test the nurse?Yes.Ms. Letby was under suspicion for the best part of a decade. She stood trial for ten months. She took the stand for fourteen days, much of it under the glare of withering cross-examination. Her every movement has been the subject of deep-sea dives by an army of keyboard warriors: your correspondent is but one.What behaviour would we look for? We might expect to catch her in the act, or in possession of medicine or instruments she cannot explain. We might expect incriminating CCTV footage. She may be overheard saying incriminating things. We might expect some documented mental illness, psychiatric issues or some criminal propensity in her background. We might expect her immediate colleagues to harbour suspicions about her. We might expect them, at the very least, to be uneasy around her.What have we seen?In the round, a striking lack of the characteristics you would expect of someone committing serial murder. No direct evidence. No possession of incriminating implements. No CCTV footage. No history of mental illness, emotional abuse or criminal propensity. And her immediate colleagues, to a person, attest they had no concerns about her behaviour. Even the hospital consultants, in their first meeting with the police, conceded as much:As part of the review staffing was looked at, there was a notable high statistical relationship between a member of the nursing staff and babies deteriorating in the unit. There is no evidence, other than coincidence.Now, it is not necessarily fatal if there are none, or few, of these things — one thing a master criminal must do is camouflage her incriminating traits — but it makes our base rate case — “the identified nurse is a serial murderer” — even more improbable.The charge selection method[...] This is after all the basis of our concerns and I think for the police to have their interest piqued we need to have that with all of the cases (it’s not going to be in the info Ian H/Stephen C have given to the police). I have attempted to do this as belwo [sic] for the ones I was involved with but hopefully more In a stating the facts way than a subjective finger pointing way.If everyone is in agreement we should all do something similar for the ones we know about. Time is of the essence, I would like to get this to Superintendent Wenham by the middle of next week at the latest.Ravi—Email from Ravi Jayaram to Consultants at the Countess of Chester Hospital, 4 May 2017What about the Crown’s charge selection method, then? We start by estimating the chance of a nurse being on duty for a given shift. Let’s give Ms. Letby the benefit of the doubt and say it was ⅓. It is from here that the improbability of Ms. Letby’s coincidental presence flows — multiply ⅓ by itself to get the cumulative probability for each successive collapse. By the time you have done this 25 times, it is a very small number indeed.But only if you selected collapses and without reference to Ms. Letby.If your “sample space” of shifts from which you are selecting suspicious events comprises only shifts on which Ms. Letby was working, her chance of being on duty for a given shift is not ⅓, but 100%. You can multiply 100% by itself as many times as you like, and you still get 100%.So it is important to be sure the sampling was done in a way that did not pre-judge Ms. Letby. If the sample excluded collapses or deaths where she was not present, then that, too, is problematic: this is like your coin hustler omitting all the times he flipped his coin and got tails.Now, no one is suggesting the Cheshire police are hustlers. But we should be able to see their sampling methodology to see whether it has properly, randomly sampled the available data. This is how we check that we are not being misdirected, even inadvertently.This information should be freely available. Nor should the Crown have any reason to withhold it.But they did withhold it. The Crown declined to share that information. Mr. Myers asked for it, and was denied it. Mr. Myers applied to the court for an order that the Crown share it, and the court declined.We can assemble some of the surrounding context from court transcripts and matters inadvertently disclosed to the Thirlwall Enquiry. From the outset, the investigation was heavily focussed on the concern that there was a malicious nurse. If there was not, there was no need to involve the Police. Ms. Letby was named in the first meeting with police, well before any decision was made to engage experts or proceed with an investigation.It seems that the Crown Prosecution did not realise the significance of this confirmation bias: by way of response to Mr. Myers’ application for disclosure, Mr. Johnson admits it in a sort of vaguely double negative way: he cannot apprehend how collapses with which Ms. Letby wasn’t being charged could possibly be relevant to collapses for which she was:...it would be fairly odd if in investigating what else she may or may not have been up to, they weren’t looking at cases where she was there.Of course we were only looking at Ms. Letby’s shifts, in other words. And the Court accepted it and upheld the Crown’s refusal to disclose it as irrelevant:4. [...] Whilst the information sought, or the basis for further police inquiries into the defendant may be of great interest to the defendant herself, they are irrelevant to the issues in this case. So there is no material to disclose, there being no material that “might reasonably be considered capable of undermining the case for the prosecution against the accused or of assisting the case for the accused ... that has not been disclosed to the accused” (CPIA s. 7A). Inevitably, the investigators were looking at cases where the defendant was there, but that has nothing to do with disclosure; [...].So, back to our logical calculation. It can’t be chance: either Ms. Letby is guilty, or the Crown’s statistics are lousy.On a simple comparison of base rates, we should start by presuming “lousy statistics are more likely than a serial murderer nurse”. We have a lot of information about the nurse which we can use to update that assessment. None of it strongly suggests she is a serial murderer. We have a lot less information about the Crown’s statistical methodology, which it has refused to disclose, but what information we do have suggests it was subject to material sampling bias.This makes things look a lot less suspicious.We are back to our base rate comparison: what is more likely? Lousy statistics, or a serial murdering nurse?This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber.See also* Bayesian inference* Texas sharpshooter* Prosecutor’s tunnel visionReferences This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

Prelude: A daycare centre in New ZealandPeter Ellis was a childcare worker in Christchurch, New Zealand. A creative, flamboyant and somewhat uninhibited character, Ellis loved his job, put a lot of energy into programme planning, and would entertain children with elaborate puppet shows and somewhat provocative productions, sometimes to the point of being “risqué and outrageous”. Ellis had worked at the daycare centre for several years and was popular with children and parents alike.In 1991 a parent made a complaint. Her child had remarked that he did not like “Peter’s black penis”. An investigation ensued. Parents talked. Things escalated. The police were involved. They interviewed hundreds of children. The stories were horrific. Christchurch police eventually charged Peter Ellis with the systematic and horrendous abuse of twenty preschool children in his care.Thanks for reading! This post is public so feel free to share it.Before his trial, the police had disclosed to his legal team the statements of the 20 child complainants, as they were obliged to do. The children were all under 5. Their statements were broadly consistent. They told an appalling story.The police did not disclose the statements from nearly 100 other children — on the pretext that, since no charges were laid regarding these children, their interviews were not relevant to the criminal proceedings against Ellis.The nature of the allegations — that Ellis had abducted the children, removed them to a different location across town, ritually abused them and then returned to the daycare centre in time for pickup — made it very difficult for Ellis rebut the children’s evidence. There were no independent witnesses. He had no alibi. The consistency of the twenty complainants’ stories was striking. It was enough to convince the jury. Ellis was convicted and imprisoned.It later turned out that while the witness statements the defence did see were consistent and theoretically plausible, many of the other children’s stories were not. Some were physically impossible. Some claimed Ellis had amputated limbs the children still possessed, or inflicted horrific injuries of which there was no trace. This is presumably why police did not press charges charges in these cases.Furthermore, a significant number of children had flatly denied any abuse had happened. The defence were not told of these children either.Plainly, these statements would have enormously helped Ellis’s defence: they would have provided context in which the “credible” accounts ought to have been set. They opened the argument that the police had cherry-picked accounts from interviews with six times that many children, thereby generating a wholly misleading impression of consistency and reliability.This was a classic Texas sharpshooter: the police had ignored a greater volume of obviously made up stories, had shelved insistent denials and painted a target around the small number of outwardly plausible statements, and presented that to the defence and the jury as the whole story.All the allegations against Peter Ellis were false. Ellis did not abuse anyone.Even the “black penis” remark was explained: it arose when Ellis was showing the children how to identify the sex of a labrador puppy.That this was a catastrophic miscarriage of justice was not finally acknowledged until Ellis had completed his sentence. Though he died of cancer in 2019, the New Zealand Supreme Court took the unusual step of posthumously exonerating Peter Ellis in 2022. The case was and is a cause célèbre in New Zealand. It led to significant changes in evidence disclosure rules and a thorough revision of the interview techniques used by police and social workers.Relevance for Ms. LetbyPeter Ellis’ case shares two features with Ms. Letby’s: firstly, the danger of selective disclosure. By presenting only the collapses during Ms. Letby’s shifts and excluding the context of similar collapses when Ms. Letby was not present, the charge sheet, and particularly the staff attendance chart, creates an “artificial coherence” to one unlikely narrative — a healthcare serial murderer — whilst suppressing evidence suggesting a much more likely one — a poorly managed and under-resourced hospital suffering a cluster of collapses in desperately ill children it was not properly equipped to treat.Just as Peter Ellis could not properly contextualise the credible complaints against him with evidence of a greater number of incredible complaints, nor could Ms. Letby demonstrate that an unusual cluster of collapses was happening whether she was there or not.It is sometimes argued that other collapses were excluded because they were “explained” or “dissimilar”, but that is to beg a question the defence might wish to put before the court. Who is to say they were not similar? In what way? By whose criteria?Selective disclosure risks transforming statistical noise into an apparent guilt signal by filtering out all the circumstantial evidence pointing away from the defendant. Remove the randomness, and what remains looks like a pattern.There is another parallel: in both cases, the alleged victims were vulnerable children entrusted to the defendant’s fiduciary care.We have an instinctive, emotional reaction to protect the weak from predators. While we can be sanguine when grown men hurt one another, we are not inclined to give those who might have harmed children the same benefit of doubt. Abuse of that sacred trust is unforgivable. If, in vouchsafing children from predations of carers the odd innocente is caught in the gears, that is a price some seem prepared to pay.We see this attitude in appeals to refrain even from discussing Ms. Letby’s case, prioritising the consideration for victims’ families, however valid her grievance may be. It neither follows — exonerating those falsely convicted of offences that did not happen should hardly upset the bereaved — nor is it a suitable moral calculus even if there was an offence, but the defendant did not commit it. Two wrongs do not make a right. The victim’s damage is done: we should be doubly sure we are not compounding it with further injustice on another.Implied evidenceFew people in history have been charged with more than twenty murders and attempted murders. Fewer still where no direct evidence links them to any of the charges. But Ms. Letby has.There were no eyewitnesses. No fingerprints. No CCTV footage. No missing vials of insulin. There wasn’t even any tittle-tattle amongst the other ward nurses: inquisitors at the Thirlwall Inquiry asked them, and they all roundly denied it, in writing.No one saw Ms. Letby do anything. No one suspected her of anything. The strongest circumstantial evidence incriminating her was that she was there. That’s it. That is the clincher. Ms. Letby was at work.As causal links go, this is not strong.What made it stronger, the Crown argued, was repetition.Ms. Letby wasn’t just there for one collapse. She, and no one else, was at work for all of them. The only common thread across the twenty-two collapses was Nurse Letby.Do not underestimate the significance of this assertion. When it comes to evidence identifying the perpetrator, it is all there is.That attendance chartTo illustrate this, the Crown ginned up a “staff attendance chart” for the twenty-five shifts over the suspect period on which unexplained collapses happened. The chart set out the attendance of every nurse in the neonatal unit. As it happens, the chart wasn’t awfully accurate, but let’s disregard that for now.The chart painted a stark picture. Whereas each other nurse’s attendance was sparse, Ms. Letby shows as a uniform column of black crosses. To labour the point, it is highlighted in sort of purplish, bruised, blue. The chart invited a clear inference:Ms. Letby, and only Ms. Letby, was present at all twenty-two events. So, you know —The Crown did not present much evidence that these incidents were related, much less that they were all caused by the same person. The jury was just left to put two and two together.But that calculation is trickier than it looks.It was not a “staff rota”For one thing, the attendance chart was not, as it is often described, a “staff rota”. No one pulled this off a pinboard in the staff room and presented it in court.This was painstakingly — if not necessarily carefully — compiled and arranged by the police for the trial. It is designed not to show, but to persuade. It invites an inference.It should have been a staff rota. A staff rota would have included all the shifts in a given period, showing who was on and who was off at every moment in the hospital’s operation.Now if the “suspect period” occupied fifteen months — taking a month or so on either side of the actual charges for good luck — a staff rota would show nine hundred twelve-hour shifts. It would note every collapse, whether or not Ms. Letby was on duty, and whether or not they were explained.A staff rota would have told a very different story.It missed some eventsNor did the attendance chart, as presented in the trial, feature all “suspicious” or “unexplained” collapses. Dr. Evans claims he reviewed at least sixty unexplained collapses, so it can’t have. We do not know who selected those sixty cases, or on what basis, and the Crown did not disclose it. It may be that even these 60 were all taken from Ms. Letby’s shifts.You will hear it said that “they weeded out the explained collapses” but this rather begs the question: how were they explained? How were these cases different from the ones for which Ms. Letby was charged? Who got to decide what was relevant?Compare this to Peter Ellis’s trial: there they excluded plainly fabricated statements and kept in the handful of stories that weren’t on their face preposterous. But all statements came from an essentially homogeneous group of witnesses. They were all important context.In Ms. Letby’s case, some “innocent” collapses might have had salient features in common with the “suspicious” collapses. We don’t know: the defence wasn’t told about them. It cannot be right that the Crown is permitted to determine this behind a cloak of privilege: it must surely be tested in open court. And it is easy enough to test, if all the information is made available.This is all the more so since the defence’s case was that Ms. Letby was only in court was thanks to misapprehensions, cognitive biases and misdiagnoses by those involved in selecting cases to bring to trial.It must be germane to know which cases were not selected for trial, therefore, and why. Without this information this is the Peter Ellis case all over again.Why the other nurses are importantNow an attendance chart asserting only that Ms. Letby was present for all charges would not be controversial. It would not even be very interesting: of course she was present: she could hardly murder by remote control.But the record of the other nurses’ presence is controversial. None were charged, so it hardly matters whether they were on duty or not. But they should not be on the chart. We should ask what they are doing there.It is, of course, clear: they are there to make that key identification point, which otherwise is strangely lacking from this case.There is one common thread here: Lucy Letby.How did the chart get into evidence?The staff attendance chart is not evidence but advocacy. It is all the more damning because it looks like evidence. No one seems to have noticed it wasn’t evidence: the defence appears not to have taken the point. So the question arises: just how did it get into evidence?A summary document compiled from other sources is, on its face, “hearsay” evidence. These days, hearsay may be admitted in criminal proceedings, where its “probative value outweighs potential prejudicial effect”. But the methodology used to create the document must be reliable, no better evidence must be available, and the prosecution must call a witness to verify the document, its accuracy and how it was compiled.None of these seems to have happened. Defence barrister Mr. Myers appears to have regarded the prosecution as “entitled” to present the chart by way of summary of their evidence, though he was critical of it. I am no criminal lawyer, and my lecture notes from the Laws of Evidence hail from the far side of the planet and date from 1992, but it is not obvious how this document was even allowed before the jury given its obviously prejudicial effect, and its lack of probative value.Do get in touch if you know the reason.How were the charges selected?It may be that the Crown’s incident review was thorough and methodically sound. It might have scoured every one of the 900-odd shifts, fastidiously assembling its final list of “suspicious” collapses by reference to defensible criteria without regard to who was on duty for any of them. It may be that, having done that, the Crown was left with 22 events from the fifteen months, and every one involved Ms. Letby.If so, that would likely be the end of it: if the sample is fair, the odds against Ms. Letby’s presence at all 22 events in those circumstances by chance are truly astronomical. That identification evidence would be compelling.But that is a big “if”.All the same, it is an “if” the Crown could easily have answered. Mr Myers asked it to, in January 2023. But it chose not to, citing “irrelevance”. Rather peremptorily, the court agreed.I have just a fragment of a scroll from the application. It is articulated in the impenetrable bluster that passes between silks, so I have translated it back into passable English as follows:Mr. Myers: We are concerned that the Crown only investigated cases where Ms. Letby was on duty. We are seeking disclosure so we can see to what extent Ms. Letby’s presence was a “search term” for the events the Crown investigated.Mr. Johnson: Well, it would be odd if we didn’t think there was a solid case against Ms. Letby, wouldn’t it? And so, wouldn’t it also be odd if we weren’t looking at cases where Ms. Letby was present?So, confirming or denying whether we looked at cases where she wasn’t there has nothing to do with our disclosure obligations under the Criminal Procedure Investigations Act.Mr Johnson’s logic is plain. How are collapses Ms. Letby isn’t being charged with possibly relevant to collapses for which she is? But he made a subsidiary concession that gave the game away: In his full barristerial English he said:...it would be fairly odd if in investigating what else she may or may not have been up to, they weren’t looking at cases where she was there.Of course we were only looking at Ms. Letby’s shifts, in other words. And the Court accepted it and upheld the Crown’s refusal to disclose it as irrelevant:4. [...] Whilst the information sought, or the basis for further police inquiries into the defendant may be of great interest to the defendant herself, they are irrelevant to the issues in this case. So there is no material to disclose, there being no material that “might reasonably be considered capable of undermining the case for the prosecution against the accused or of assisting the case for the accused ... that has not been disclosed to the accused” (CPIA s. 7A). Inevitably, the investigators were looking at cases where the defendant was there, but that has nothing to do with disclosure; [...]5. In these circumstances, there is no reason to doubt the prosecution’s response to this application that the material requested is not disclosable under the CPIA.Both Mr. Johnson KC and Mr. Justice Goss appear to regard Mr. Myers’ application as a slightly cheeky fishing expedition: designed see what else the Crown might have up it sleeve that could lead to more charges — as if that was what Mr. Myers was after.In fact, Mr. Myers wanted to know quite the opposite: how far had they considered collapses that didn’t incriminate Ms. Letby?Mr. Johnson gave his answer: he hadn’t. The Crown had their woman: it was Ms. Letby.Let’s return to Peter Ellis for a moment and consider what Ellis was confronted with, compared with what he might have seen had the crown disclosed everything (this is hypothetical data by way of illustration):Charged with:Credible allegation of harm by Complainant ACredible allegation of harm by Complainant BCredible allegation of harm by Complainant CActual Picture:Credible allegation of harm by Complainant ADenial of any harm to anyone by Witness DNon-credible allegation by Witness EIncoherent babbling by Witness FNon-credible allegation by Witness GNo knowledge of anything by Witness HNon-credible allegation by Witness IDenial of any harm to anyone by Witness JCredible allegation of harm by Complainant BDenial of all harm to anyone by Witness KNon-credible allegation by Witness MCredible allegation of harm by Complainant CDenial by Witness NNon-credible allegation of harm by Witness OAnd apply the same filter to Ms. Letby’s situation (this is hypothetical data by way of illustration):Charged with:Unexplained collapse Baby A: Ms Letby on dutyUnexplained collapse Baby B: Ms Letby on dutyUnexplained collapse Baby C: Ms Letby on dutyUnexplained collapse Baby D: Ms Letby on dutyActual Picture:Unexplained collapse Baby E: Not presentUnexplained collapse Baby A: Ms Letby on dutyUnexplained collapse Baby F: Not presentUnexplained collapse Baby G: Not presentUnexplained collapse Baby B: Ms Letby on dutyUnexplained collapse Baby H: Not presentUnexplained collapse Baby I: Not presentUnexplained collapse Baby C: Ms Letby on dutyUnexplained collapse Baby J: Not presentUnexplained collapse Baby K: Not presentUnexplained collapse Baby D: Ms Letby on dutyUnexplained collapse Baby L: Not presentIt tells a very different story.Interlude: the unique nature of healthcare serial murder casesThere is something else to bear in mind about this case. During the suspect period, it was by no means clear that anyone was attacked, let alone murdered at the Countess of Chester Hospital. At the time they happened, many of the collapses prompted further tests, examinations and post mortems. None resulted in suspicions of foul play.In murder cases, not being sure that anyone has, in fact, been murdered, is quite an unusual state of affairs.In serial murder cases — except in one type of case — it is almost unprecedented.Usually, no-one doubts there’s been a murder. Body parts are found clogging up drains, turned into lampshades, in shallow graves, under floorboards or riddled with gunshots.Usually, there is strong evidence implicating the defendant: eyewitness evidence, fingerprints on the gun, or it being the defendant’s drain, bath, garden or crawlspace where the bodies were found.That one exception is healthcare serial murder. This type of case is strikingly different. Usually, there is doubt there has been a murder. Usually, there is no direct evidence implicating the accused. Often, the evidence is entirely circumstantial.Ms. Letby’s case is a perfect example. The inference that there has been foul play comes, predominantly, from technical evidence: proposed air emboli. Immunoassays. Insulin and C-peptide readings. These are matters requiring deep expertise and subtle inference well beyond my meagre faculties. I am not going to express any view on medical evidence I have no hope of comprehending other than to say that people who are field-trained endocrinologists and neonatologists seem vigorously to disagree with each other about the technical evidence in this case.Remember, the standard the Crown must attain is beyond reasonable doubt. If experts in the field are disagreeing about it, there is reasonable doubt, Q.E.D.But this is as may be. We are here talking about evidence specifically implicating Ms. Letby, and no-one else, as the author of categorical crimes, presuming they can be proven to have occurred.The major evidence in this regard — almost the only evidence in this regard — is her opportunity: Ms. Letby seems to have been the only one on deck when every incident happened.But if that evidence falls apart, as it seems to have, what remains that identifies Lucy Letby as the perpetrator of any crime at all?See also* The Letby collection* Texas sharpshooter* Plain EnglishThis Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

Show me a man who believes in conspiracy theories and I’ll show you someone who has never organised a surprise party.—Lee Harvey Oswald.The constant presenceOrdinarily, when a defendant appears on 22 counts of things like murder, there is a wealth of compelling evidence: eyewitnesses, fingerprints, incriminating forensics and related corroborations that point not just to murder, but to the defendant, specifically, committing each one.Ms. Letby’s case seemed quite different. The evidence largely focused on whether, in each case, there had been a crime at all. Expert evidence challenged the presumption that the collapses were just part of the ordinary run of medical emergencies one would expect in a busy intensive care unit.There was a curious missing step: the prosecution seemed founded on the tacit assumption that, as long as they could prove these to be malicious acts, it went without saying that they were carried out by Ms. Letby. This, it implied, could be inferred by her “constant presence”.Was that tacit assumption justified?This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber.Prelude: tragedies in the airOn October 29, 2018, a Boeing 737-MAX operated by Lion Air, a carrier operating in Southeast Asia, crashed into the Java Sea, killing all on board. Five months later Ethiopian Airlines, a carrier operating in Africa, lost a Boeing 737-MAX when it crashed into farmland near Bishoftu.At around the same time, there were a series of other air accidents: an Air Niugini Boeing 737 crashed into a lagoon in Micronesia. A Fly Jamaica Boeing 757 overran a runway in Guyana. A Saha Airlines Boeing 707 crashed in Iran.Though all involved Boeing airliners the crashes seemed, as air crashes generally do, unrelated: they involved different airlines, on different continents, at different altitudes, over different terrain, at different times of the year and in different weather conditions.Air crash investigators were called in and began to review the black box flight data records.They soon began to notice unusual similarities between the two 737-MAX crashes.MCAS: a villain in the roomSometimes, when you look closely, the circumstances surrounding apparently unrelated events are so similar as to invite the inference that they have a common cause. Airline crashes are vanishingly rare and, except where planes crash into each other, are almost always unrelated.They tend to arise from a complex mix of causes: pilot error, terrorism, atmospheric conditions, garbled air traffic control instructions, freight loading, autopilot mis-programming, mechanical malfunctions and even ground-to-air missile attacks. Each tends to be sui generis because the global aviation system learns from its mistakes. It is very good at isolating, minimising and not repeating catastrophic risks.The two 737-MAX crashes stood out. They were uncannily similar. Both airliners were more or less brand new. Both crews experienced erratic altitude changes shortly after takeoff. In both cases, the computerised navigation system repeatedly, inexplicably, forced the plane’s nose down while the crew struggled to force it back to level. In both cases, the autopilot eventually overrode the crew’s manual intervention, whereupon the planes plunged irrecoverably towards the earth.Air crash investigators soon identified a common culprit: Boeing’s state-of-the-art “Manoeuvring Characteristics Augmentation System” (MCAS) was installed on both airliners.“MCAS” was designed to automatically push the plane’s nose down in certain conditions, to prevent stalling. But it relied on readings from a single “angle-of-attack” sensor, with no redundancy if it failed. When the sensor provided incorrect data, as it did in both cases, MCAS repeatedly forced the nose down. Boeing had not alerted airlines about the new system, and pilots were not trained how to manage it. The system could, in any case, override pilot inputs and there was no easy way to disable it in an emergency.For those two 737-MAX crashes, there was a single villain in the room: MCAS.A villain in the room at Countess of Chester?With that analogy in mind, we come to the Countess of Chester Hospital in 2016. It had suffered, in effect, a series of baffling air crashes over a short period. But what had caused them? Was they just part of a random cluster, or was there a proverbial villain in the room?Like airline accidents, individual hospital collapses tend to be independent. Each patient arrives with her own pathology, and her outcome depends on how effective the hospital treatment is on her pathology. Generally, when patients die, it is because the hospital could not save them, rather than because something else at the hospital killed them.This is not necessarily the case, of course. But if something, or someone, at the hospital is creating collapses, we should expect an improbable convergence of knock-on effects: symptoms, conditions and outcomes that indicate there is a common cause, just as we would with related air crashes.We should expect corroborating evidence.A word about the standard of proofAquick reminder that the Crown must make the running in a criminal trial. Proving guilt is thoroughly, at times tediously, analytical. Each crime is made up of a set of legal components. The Crown must satisfy the jury of each one. It does that by presenting evidence — facts — to support each legal component. This exercise is no sense “impressionistic”. It is painstaking, and exacting. It is why criminal proceeedings take as long as they do. You have to prove even obvious things, that no-one seriously doubts.There is a major distinction between “law” — the legal components comprising a crime — and “fact” — the evidence presented to “prove” those components. Law is for the judge; facts are for the jury. A big part of the judge’s job is to guide the jury as to the legal components. The judge will slowly and carefully walk the jury through the logic of components they must navigate to reach their verdicts. Once that is done, what they do behind closed doors, on the other hand, is a mystery.In any case, the standard of proof for each component is very high: in the vernacular, the jury must be satisfied “beyond reasonable doubt”. The Crown must bring compelling evidence to support every component of every offence.Strikingly similar evidence and the serial murderer’s modus operandiThis can put a prosecution in a dark place. Especially if it is dealing with a sophisticated criminal. Serial murderers generally only get away with it long enough to become “serial murderers” by not leaving incriminating evidence lying around. They avoid being seen by those who live to tell the tale. They are meticulous in cleaning up after themselves. That makes them hard to find, and even harder to convict.But, that is how it is: just because the perpetrator is a wizard that does not mean the Crown is excused from meeting its evidential burden. “Beyond reasonable doubt” means what it says: to convict a defendant of multiple murders, you must prove every aspect of every one.Now, a serial murderer may have a unique modus operandi. She may keep trophies. She may leave a kind of grisly calling card — a bullet-holed queen of hearts on the forehead, say — unusual enough to permit the inference that, if the “Lonely Hearts Killer” did that one, then he must have done these ones, too.The law has developed strategies to accommodate these “signatures”. One is the “strikingly similar” evidence rule: the Crown may present incontrovertible evidence that a defendant committed one offence to prove that she must have committed another if the offences, or how they were committed, are so “strikingly similar” that they function as a “behavioural fingerprint”.The courts will not infer such a thing lightly, however: a “signature” needs to be strong enough to support the inference, that the defendant’s involvement is the only plausible explanation.It must be highly unlikely to occur by chance or to be independently replicated by a different perpetrator. If so, this is a convenient heuristic for police: it saves them having to find eyewitnesses for all the bodies stacked up in the county morgue that are decorated with bullet-holed playing cards. The defence may defeat the argument by presenting evidence and argument rebutting those inferences.Here there was very little direct evidence implicating Ms. Letby for the charged offences. If the Crown wanted to claim she had nevertheless left behind a “behavioural footprint”, it had two problems.Non-similarityThere was premeditation, calculation and cunning in your actions. [...] You used a number of different ways to try to kill them, thereby misleading clinicians into believing the collapses had, or might have had, a natural cause or were a consequence of a developing medical condition.—Mr. Justice Goss’s sentencing remarks, 21 August 2023.Firstly, the collapses weren’t strikingly similar. To the contrary, if things were as Mr. Justice Goss saw them, Ms. Letby was artful in how she switched up her methods to make the offences look different. The Court cited this very calculatedness as a measure of her cruelty.According to the Crown, Ms. Letby attempted murder, variously, by injecting air into infants’ bloodstreams, pumping air into their stomachs, administering factitious insulin, overfeeding, tampering with breathing tubes, disabling oxygen saturation alarms and, in one case, physical violence.But it produced no evidence of Ms. Letby, herself, actually doing any of these things.This seems to be a long way from “striking similarity”. There is no “signature” to these events, let alone anything intrinsic that distinguishes them from accidental medical emergencies.The Crown might assert that Ms. Letby was simply so cunning that she avoided leaving evidence. But it must produce evidence of that acuity. It does not seem to have done so.The Crown needed, therefore, to produce cogent evidence tying Ms. Letby, specifically, to every allegation: if not direct eyewitness evidence, then cogent circumstantial evidence that it can only have been her.It didn’t have a lot of this, either.Non-identificationSecondly, the only “striking” thing about the identification evidence was how weak it was. There was evidence that the collapses were “consistent with” someone’s deliberate harm — the allegedly factitious insulin, for example — but little of it pointed to an individual, let alone Ms. Letby.This becomes clearer when taking the evidence for each charge in isolation. Take the following hypothetical:If this charge were laid by itself, would there be enough evidence to find Ms. Letby guilty of murder beyond reasonable doubt?The best case to do this is Child K, because it was (re)tried alone, albeit against a background of Ms. Letby’s existing convictions. It also featured what the Crown considered the strongest evidence directly incriminating Ms. Letby: the “virtually red-handed” episode.“We say Lucy Letby had been caught virtually red-handed by Dr. Jayaram.”—Nick Johnson, KC, opening in the retrial of Child K, 12 June 2024.Mr. Johnson KC opened the Crown’s case in the retrial as follows:“So, when Dr. Jayaram walked into the nursery, he saw Lucy Letby was standing over [Child K] and her blood oxygen levels were falling, but the alarm was not sounding. Not only that, but Lucy Letby was doing nothing.We say that, in those circumstances, the only reasonable thing for a nurse to do would be to call for help and/or use the Neo puff to breathe for the child.” The Crown alleged Ms. Letby tried to suffocate Child K by dislodging his breathing tube and switching off his desaturation alarm. According to this narrative, the infant was only saved by Dr. Jayaram’s timely intervention.But no one saw Ms. Letby dislodging the breathing tube or disabling the alarm. Premature infants are tiny, move around a lot, and often dislodge their own breathing tubes. Another witness recalled hearing the alarm sound. Nor was there evidence it had been disabled or interfered with.The “clincher” was Dr. Jayaram’s evidence. He told the court he entered the room to see Ms. Letby standing over Child K’s incubator “doing nothing” while the infant collapsed.But by itself, this is hardly strong evidence. It is a single account. It hardly rebuts all possible alternatives. We need not be detained by details, beyond emphasising that, on the evidence, Ms Letby’s behaviour was also “consistent with” not having tried to murder the infant. There was still plenty of reasonable doubt.Whence a “signature”, then?Well, Mr. Johnson KC alluded to one when he framed his case to the jury. It is subtle, though, so keep your eyes peeled:“The reason [Child K] was desaturating was because that the breathing tube had been displaced and we suggest that the fact Lucy Letby was doing nothing and the fact the alarms were not sounding is evidence from which you can conclude that it was Lucy Letby, the convicted murderer, who had displaced the tube.”There is only one reason for that parenthetical: Ms. Letby has already been convicted: that is the “signature”.That is the Crown’s best chance of buttressing the meagre identification evidence for the immediate case.But what are the odds—There may be one last way the Crown might string something together. It doesn’t sound promising — pro-guilt commentators are easily riled by the suggestion that this might have anything to do with it — but there might be a case that statistics could provide the missing “signature”.If the probabilities bear out the Crown’s theory, it may still have a compelling prima facie case that Ms. Letby was the murderer.She says she was there by coincidence. We can measure that claim against the probability of it being true. If, as Ms. Letby says, the collapses had nothing to do with her — this is what statisticians call the “null hypothesis” — as far as she is concerned, they are random events.The question to ask is this:What are the odds that a full-time nurse would be on duty for 22 randomly chosen events by coincidence?We can make a rough estimate.We know Ms. Letby worked hard. Even with overtime, after weekends and holidays, she would have worked no more than one-third of all shifts. Let us give her the benefit of doubt and say she consistently worked a third of all shifts. Her chance of being on duty for any one shift was, therefore, ⅓. Thirty-three per cent.A little bit of maths, then: to find the probability of several events all happening, you multiply their individual probabilities. If there was a 33% chance of Ms. Letby being on duty for one shift, then the chance of her being on duty for all of twenty-two randomly-chosen shifts is 33% multiplied by 33% twenty-one times. Thirty-three per cent raised to the power of 21.This is a very small number. It is about one in 10.5 billion. There was a one-in-ten billion chance that Ms. Letby was rostered on for all suspect shifts by coincidence.For the less mathematically inclined, that is, effectively, zero chance.If the suspect shifts really were selected independently, we have our signature.But it’s a big “if”.To run it down, there are two further cross-checks to make.Selection methodFirst, how were the offences selected? Were they, from Ms. Letby’s perspective, really random?The damning probability calculation above only works if it is true there was a ⅔ chance Ms. Letby was not there for any particular shift.But this presumes the police reviewed every single shift looking for suspect collapses “blind”: without any regard to who was on shift. If their methodology was different — if Ms. Letby was the prime suspect from the get-go, and they only considered her shifts when looking for collapses, then her probability of being on duty would not be 33%, but 100%. A certainty.In this case, the chance of Ms. Letby being coincidentally on duty for all suspect shifts was 100%. Of course it would. The attendance chart with all those crosses in it tells us nothing.So, how were the events selected? This is a fascinating question. I discuss it in “How did the police select the charges?”How to explain missing corroborationSecondly, if police did select the suspect offences blind, without reference to Ms. Letby’s presence and, probabilistically, Ms. Letby was therefore connected to the collapses, then if it were murder, we would expect consequential facts to be present. No action exists in a vacuum. No action is devoid of antecedents and consequences, least of all highly unusual ones like premeditated murder. Where are those consequential facts?Where, indeed, are antecedent facts consistent with such outlying behaviour? It is hard to predict the future state of a complex system: I have bloviated at length about this elsewhere. It is much easier to trace its history. Where are the background circumstances that would lead a person to do such a thing?This too is fascinating. I cover it in “Must the crown prove a motive?”See also* Lucy Letby* Conspiracy theory* Base rate neglectThanks for reading! This post is public so feel free to share it. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

The test results showing that insulin had been given to them was the only piece of concrete evidence of criminality throughout the whole of the prosecution’s case. It was the closest thing they had to a smoking gun and became the keystone for their case as a whole.Johnson’s argument ran that if the jury could agree that Letby had deliberately poisoned two babies, they could also reasonably conclude that she had harmed others using different methods, even if the evidence for those were less concrete. In the event, the insulin cases were the first on which the jury reached a verdict.—The actual evidence against Lucy Letby, The Times, February 5, 2025One flash of lightBut no smoking pistol.—David Bowie, Ashes to Ashes (1979)Of all the strands of Lucy Letby’s trial, the insulin evidence is the most difficult — in that it is hard for non-specialists to fathom — but also pivotal, as it is the only “smoking gun” in the whole case. Unlike any other piece of evidence, it seems unequivocally to suggest actual malice.But that is to beg a large question, so let’s back up a bit.Now I am no kind of expert about anything much, and certainly not glycaemia. Talk of picomoles, immunoassays and C-peptides alternately bores and intimidates me. So we can leave all that to the experts — perhaps with the marginal note that it is so difficult even they don’t seem to be able to agree about it — and talk instead about the test results, in the round, as evidence.This Substack is reader-supported. To receive new posts and support my work, consider becoming a free or paid subscriber.Start at the very beginning —As with many of the allegations in this trial, the Cheshire police appear to have started investigating at the end — nearly the end, at any rate: there was a later twist — and then worked backwards. I can’t help wondering how different the outcome might have been had they only started at the beginning.Their original focus was this:Scientific tests suggest two children, Baby F and Baby L, were administered “factitious” insulin.Since they were not prescribed it, and no one owned up to accidentally administering it, this points, presumptively, to malice.Even without understanding how immunoassays work, we can see this is still not open and shut: it is circumstantial: it requires an inference that dirty work is afoot.Without better evidence, it weighs on the prosecution’s side.But there may be better evidence. It may undermine that inference.For one thing, the test may not have been reliable: perhaps the apparatus was mis-calibrated. Maybe the sample was contaminated. Perhaps the result was a false positive. Maybe the examiner misread it.But even before doing that, we should first look with an open mind for positively innocent explanations. For, all other things being equal, deliberate insulin poisoning on a neonatal ward is not common. Over the history of healthcare, it has not happened very often.If the odds are there is a more likely explanation, the least we should do is look for it.But it doesn’t seem the Cheshire police did this with any great gusto. Rather, armed with their burgeoning theory of an angel of death on the ward — probably with a particular “death angel” in mind — the police saw a smoking gun. They spent little time looking for innocent explanations. They spent little time corroborating this one.They had their suspect.This might come to be seen as an oversight. For if there has been an insulin poisoning, we would expect other evidence to corroborate it. We might ask who accessed insulin. We might ask whether any insulin was missing. We might look for tell-tale signs of tampering with drip bags. And we might want some evidence that Ms. Letby had had something to do with it.Remember the burden of proof: the Crown must show beyond reasonable doubt that this was factitious insulin, and that it was maliciously administered, and that Lucy Letby administered it. The Crown had a prima facie case for this first limb, but nothing to support the second or the third.Unasked questionsOnly very small volumes of insulin needed to be added to the half litre bags of feed; it was not noticeable in the bag, nor would it be apparent that any was missing from the insulin bottle.—Sentencing Remarks, Mr Justice Goss, August 21, 2023Now: absence of evidence is not evidence of absence, sure. But when we find absence after absence of evidence where, on a random roll of the dice, once in a while you would expect to find some — if, on every roll, the evidential dice keep coming up snake-eye — we should be asking questions.No matter how brilliant a criminal mastermind, a killer would have to get some insulin from somewhere and insert it in the feed bags somehow. All other things being equal, you would expect evidence for these necessary steps to accumulate. The more consecutive absences there are, the more this begins to feel like improbability.And even if we find none — a successful villain covers her tracks, after all — we should at least expect evidence to point away from other innocent explanations. So, let us see:Was there evidence of Ms. Letby taking or requesting any insulin?No.There are no documents, witnesses, or physical evidence (even consistent with Ms. Letby accessing insulin. The prosecution implies she could have taken it opportunistically from the unit’s supply — and logically, this is true, but the fact remains: there is no evidence that she did. Absence of evidence is not evidence of anything.Is there evidence any insulin went missing?No.Stock checks weren’t detailed enough to confirm missing insulin, but it is still true that no discrepancies were recorded. The Crown might say the amounts involved were small enough to go unnoticed — and logically, this is true, but the fact remains: no tangible loss was recorded. Absence of evidence is not evidence of anything.Is there evidence of Lucy Letby tampering with any feeding bags?There were no eye-witnesses, and no forensic evidence on any of the bags linking her to any tampering with it. No fingerprints, no puncture wounds, no traces of insulin found where they should not have been. Modern feed bags have sterile ports through which one can introduce medicines, so there was no need to puncture the bags, and the Crown might say the bags were thrown out before they could be checked — and logically, this is true, but the fact remains: no-one saw any reason to check them. Absence of evidence is not evidence of anything.Is there evidence any feeding bags were tampered with at all?The bags were discarded as part of routine practice without being checked. The prosecution’s theory assumes they were tampered with — and logically, it is true, they could have been, but the fact remains: there is no evidence that they were. Absence of evidence is not evidence of anything.Is there evidence Ms. Letby researched insulin, or insulin poisoning, on the internet?And the police looked. They searched her devices and home. They dug up her garden. Ms. Letby might have been a zen master of surreptition in every other dimension of her criminal enterprise, but she was incautious about her internet search histories. Yet the police found no searches about insulin — nor for that matter, air embolus, overfeeding by milk or liver damage by Vulcan mind-meld. The prosecution might argue that, being a diligent nurse, she already know this anyway, but still. Absence of evidence is not evidence of anything.Not only was no such evidence uncovered, as far as we know, no one really even looked for it. The police had their smoking gun, their expert witness was on his way from wales, so poor old “Nurse Death” was for the high-jump.This consistent absence of evidence in scenarios where, on another day, evidence might exist, start to resemble a different kind of smoking gun.And that is before we consider the twist.That twistImentioned at the top that the police started their investigation near where it should have ended. This where they found their smoking gun: the insulin tests results raised a strong presumption of foul play.Though not an endocrinologist, lead prosecution expert Dr. Evans thought it was indisputable.Others would later disagree with his assessment — after the trial — but one thing all experts have consistently agreed on is that the readings, irrespective of their reliability, were extremely high. This is how the Cheshire police could be so confident of bringing charges in the first place.Now, back to our theme of “unasked questions”. How reliable were these tests? Dr. Evans has often spoken about the unequivocal implications of these results, but rarely about their likely accuracy. But if they were accurate there is an unfakeable, unhideable piece of corroborating evidence you would expect to see. You would expect the victims to fall into a coma and then die. Not certainly, if diagnosed and treated instantly, but very probably.So here is the twist, which happened just after the point at which the police drew all their conclusions:Both infants survived.Now — we are in the world of probabilities. Survival is possible, but it was not the most probable outcome if the test results were correct.So, here is another “missing” corroboration: the most probable clinical outcome of the test results, if they were accurate, didn’t happen.So, if this was a murder attempt by massive insulin overdose — and that’s unusual enough in itself, remember— and if the doses really were as big as the test results suggest they were, then the fact that the attempts failed is even stranger.This really is the most unlikely case.An alternative explanation, apparently not considered at the time, was this: the test results were wrong. This was an “ordinary” neonatal hypoglycaemic episode. No malice was involved.Now: there is a counter-argument the prosecution might put here. It goes like this:The NICU specialists at the Countess of Chester Hospital were a crack squad of experts and only their swift intervention defeated Ms. Letby’s grim machinations and saved the day.Okay: let’s go with that, though — honestly? — it is something you’d expect a master manipulator and criminal genius to have thought about beforehand. It significantly reduces her chance of success and greatly increases her risk of detection.In other words, isn’t the slow-release of a massive dose of insulin under the watchful eyes of a crack squad of neonatal experts in an ICU which is monitored up to the hilt, a spectacularly bad way of surreptitiously committing murder? And isn’t it all a bit Batman villain?Selection bias?Now there is another implication of the children’s initial recoveries. It calls into question how, and why, the prosecution selected the events with which Ms. Letby was charged in the first place. Particularly these ones.An episode of hypoglycaemia followed by a recovery is not an inherently suspicious event in a neonatal unit. In fact, premature infants are somewhat prone to it. So much so that you would not expect such an episode to be reported on datix, or registered as a “near miss”, or anything like that. It might be recorded, but it would merge into the background noise of hospital data flying around: over 15 months, and 1,300 shifts, you would not expect “hypoglycaemic episode with recovery” to stand out. Especially not if your frame of reference was “unexpected infant mortalities”.And so it seems: when the test results came back they were logged, but no-one acted on them. They were filed. They did not show up as evidence of “foul play” until the police investigation in late 2017. By this point, Ms. Letby was already in the crosshairs.So what happened? Did prosecutors stumble randomly on these records, unremarkable though they were, pull them up, get somehow hinky about them, and only then realise that, by crikey, Ms. Letby was on duty when these episodes occurred?Or did it happen the other way around? Did they isolate all Ms. Letby’s shifts and drill into them, looking for anything they could find?This might seem a small point, but in the context of the “dodgy shift rota” — the only piece of identification evidence positively implicating Ms. Letby — it is massive.“Man with a hammer” biasWe are pattern-matching machines. When we are artificially motivated to find certain patterns and discouraged by system incentives from looking for other ones, we get good at zeroing in on what we are hoping to find. If you had to design laboratory conditions that were optimised for prosecutor’s tunnel vision, you could scarcely do better than what we have here.This is a form of remunerated confirmation bias. Experts, particularly, are primed and motivated to see patterns that conform to existing structures in their professional calling — call this “expert validation bias” or “man with a hammer” bias. Experts are no different from the rest of us: we all construct our world using tools already in our shed.Experts are also motivated to embrace narratives that promote their own professional significance (you might call this “make way, I’m a doctor” bias, though it is really just an aspect of expert validation bias).Police officers exist to find crimes.Prosecutors exist to deliver convictions.Expert witnesses see what their clients want them to see. The Crown Prosecution Service is not in the habit of engaging expert witnesses to blow up its prosecutions.Disconfirmation biasOne way of disarming this systemic confirmation bias would be to incentivise, or somehow compel, the Crown to actively seek out gaps in its own case: missing corroborations that one would expect to find were the prosecution theory true. To introduce some disconfirmation bias, in other words. Actually, it is supposed to do this already, but it is a rule honoured in the breach.If your theory is that a dead-eye marksman has been potshotting a single point on your Texan barn, a thorough review of the rest of the barn, surrounding trees, fenceposts and nearby outhouses for bullet holes will give a better picture of your barn: that is, one without a target painted on it.This is not how an adversarial system naturally behaves: it expects each side to aggressively promote its own interest. Plainly, the prosecution cannot be expected to lean doggedly into the pursuit of exculpatory evidence even if it is meant to, but the defence certainly can.But this somewhat undermines the sacred precept of criminal liability: the burden of proof is on the prosecution. It should not be — is not — the defence’s job to prove anything. After all, how is an innocent defendant supposed to know how an alleged crime went down?Furthermore, in certain cases, and Ms. Letby’s is one, the vital exculpatory evidence may lie within the prosecutor’s confidential possession. For example, what was the prosecution’s methodology for selecting suspicious events? The CPS has declined to say, but seeing that the consultants named Ms. Letby when they first met with police, it would not be a surprise to discover that, in Mr Myers’ ungainly phrase:[Ms. Letby’s presence] has, in effect, become a search term and a parameter for bringing a prosecution.On not asking questions you won’t like the answer toProsecutors may be supposed to open-mindedly challenge their own theory of the case, but the rules of court procedure positively disincentivise them from actually doing it. Should they look for disconfirming evidence, and find it, they must at once turn it over to the defence. This hardly encourages them to chase down potentially exonerating lines of enquiry. If you ask a silly question, you will get a silly answer. So do not ask silly questions, being ones you do not want to know the answer to.Theoretically, there are safeguards against this behaviour: prosecutors have an abstract duty to seek exculpatory evidence, and there is judicial oversight of the disclosure process, but these are hard to enforce, and, and judging by recent experience — the Post Office Horizon debacle refers — don’t work very well. They are especially ineffective early in an investigation before charges have been laid. Who then is watching over the police’s shoulder making sure they ask themselves hard questions?Nor do they really address the fundamental problem of “not asking questions you don’t want to know the answers to”.Were prosecutors required to file with the court not just a charge sheet but a table of alternative theories they’d considered and the steps they’d taken to test these theories, and their rationale for dismissing these alternative explanations, this would create direct judicial oversight of investigative thoroughness and would give defence a stick with which to beat lazy prosecution teams. This may create additional costs and place additional burdens on police and prosecution teams, but if applied at a significant threshold, this would seem a justified burden in light of the potential consequences of criminal conviction. Ms. Letby is, after all, serving fifteen whole-life sentences for something it seems quite likely she didn’t do.See also* Texas sharpshooter* Confirmation bias* Absence of evidence is not evidence of absenceThanks for reading! This post is public so feel free to share it. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

“Lucy Letby Conspiracy Theorists are Wrong”, Liz Hull, Daily Mail, July 5, 2024.R v Letby, Court of Appeal Judgment, 2 July 2024.Rachel Aviv’s, New Yorker investigation of 13 May 2024.Lucy Letby: initials of babies noted in diary on dates of alleged attacks, court told, The Guardian, 17 April 2023. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

Serial murderers of any kind are vanishingly rare in Britain. Wikipedia lists fifty-five, since 1600. But so are miscarriages of justice. Wikipedia lists fifty-four, since 1255.Both narratives are highly improbable. Of all the explanations we might offer for the unusual spike of incidents in 2015 and 2016, as a matter of “prior probabilities” they are the least plausible: all else being equal, it is highly unlikely there was a serial murderer at work in the Countess of Chester Hospital. But, one having been convicted, all else being equal it is highly unlikely her conviction was a miscarriage of justice. This is why tempers run high. Both positions seem untenable.They leave untouched a wide range of more probable, but less satisfactory explanations. We like our narratives to explain the world to us. We do not find useful ones that say, “Well, we just don’t know”. We prefer conclusions, however unlikely they may be.So our institutions persuade us to deprive Ms. Letby of that wide middle ground in which she was an ordinary person, with pluses, minuses, virtues and failings. Neither angel nor devil: she just had the misfortune to be involved, somehow — we know not how — in these tragic events.On herd minds, groupthink and narrative biasHerculio: ’Tis neither malice, spite, nor virtueWhose ledger swells, or plucks, the seedy fruits of progress —But mainly accident.Lest thee with surety know aught else —Withhold thy assignations.Triago: Pish upon thee, Nuncle. Pish!Dost thou mean to sayThings peel this wayThrough doughty misadventure?Herculio: Peradventure —Triago: Pish abeam!Has thou no more to say than that?Wouldst thou on this shaky surmiseWithhold rebuke?Herculio: Perchance, per case, mayhap dear Triago’Twas but a fluke?Triago: O! This nuisant planet weighs upon my soul!Herculio: If ’tis this and nought besideThat flies you to a vernal rageOur fickle globe in its manifold confound’ryLies prettily indeedFor thy alignment.The full article on the JC is here.The Jolly Contrarian is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe

The collection of biases and cognitive gin-traps that can lead prosecutors — those who “prosecute” a particular theory of the world — to stick with it, however starkly it may vary from available evidence and common sense.So named because it is often literal prosecutors, of crimes, who suffer from it. This kind of tunnel vision has led to notorious miscarriages of justice where innocent people come to be convicted notwithstanding clear and plausible alternative explanations for their ostensible “crimes”.A review of the background, some famous cases, and the three phases of tunnel vision.The text for this podcast is here.Great sources:Lindy Chamberlain: A Perfect Storm: The True Story of the Chamberlains.Peter Ellis: Alexander Behse and Ali Jones’ Conviction: The Christchurch Civic Creche Case.David Bain: Christchurch Journalist Martin Van Beynen’s Black Hands.Thanks for reading The Jolly Contrarian! This post is public so feel free to share it. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit jollycontrarian.substack.com/subscribe