Very few people in the UK are convicted of one murder, but David Cook has twice been convicted of killing. Fresh out of prison Cook carries out his murderous plan and attacks pen-pal Beryl Maynard in her own home in the hunt for money. Unlike most convicted murderers, David Cook hadn't reached the end of his crimes as over twenty years later, in a small Welsh town where no one knows of his past crimes, pensioner Len Hill disappears. We lift the lid on this shocking double-killer's attack on his vulnerable neighbour.