Scots nurse Colin Norris, dubbed the Angel of Death, is serving a minimum of 30 years in prison for the murder of four elderly patients and the attempted murder of a fifth.
But new evidence to be revealed by BBC Scotland Investigates casts serious doubt on his convictions, and could pave the way for him to be set free. Reporter Mark Daly revives the style and spirit of the old BBC Rough Justice strand, by critically examining the main components of the case against Norris, and dismantling them one by one.
