164: The mysterious deaths of Margaret Chandler & Gilbert Bogle

On New Years Day 1963, two teenagers come across a man lying face down next to the Lane Cover River in Sydney, Australia. At first they assume he's drunk but soon realise that's not the case. Police later find a second body, that of a woman, located just metres away, but an autopsy was unable to find a cause of death for either... all they know, is that they died from the same, mysterious cause.