In 2015 a 69-year-old man is found stabbed in his own home. Cops can't understand it. There's no forced entry. And no obvious motive. He has no enemies. At the scene, forensics uncover a receipt from a nearby cashpoint. Cops think it will narrow down the time of death. But they're in for a shock. CCTV at the bank reveals a woman, using the victims card to withdraw cash. Who is she? And how does she relate to the murder? It turns out that her boyfriend, Ian Birley, is a man with a past. He's only been out of prison a year, after serving a life sentence for an almost identical murder. Back in 1995, while living on the streets in the town, Birley had killed an elderly man in his own home, for no real motive. Now lightning had struck twice.