Buchan theorizes that the killer believes they are a modern Witchfinder General and that the markings on both Dorothy's house and the scene of Alexander's murder are to warn off evil spirits, though homeless Lee Bysack claims they are to show houses friendly to vagrants

Cast: Rupert Penry-Jones, Phil Davis, Steve Pemberton, Sam Stockman, Ben Bishop, Hannah Walters, Claire Rushbrook, Georgine Anderson, Deddie Davies, Jake Curran, Damian Dudkiewicz, Mary Roscoe, Brian Protheroe, William Beck, Angela Pleasence