In the mid-1980’s DNA science was in its infancy. Crimes were solved thanks to witnesses, confessions, informants… not science. But in a suburb of Glasgow, in Scotland, detectives faced a case with just one witness, and no clue as to the identity of a killer in their midst. The weapon of choice was a dressing gown cord, used as a ligature. And it would prove to be the smoking gun which eventually – 30 years later – revealed a perfectly preserved piece of DNA which led officers to the door of their suspect.  Learn more about your ad choices. Visit megaphone.fm/adchoices