How do you know if a pandemic is from a lab leak?

There's been a lot of discussion about the origins of COVID, especially on the question of did it come from a lab, did it form naturally - or maybe a mix of both.Well a new book called Dark Winter has tackled this question and has come to the conclusion that we better get better at identifying outbreaks - because sometimes they're intentional.While there's no direct evidence that COVID came from a lab leak, author and Professor Raina MacIntyre argues it is possible and some have been too quick to wave away the possibility.