Suspects - Season 2 Episode 1
Nobody Else (Part One)

In the first of a two-part story, DI Martha Bellamys neighbour, barrister Jonathan Moxton, is discovered at his home with serious head injuries, his wrists bound with a belt and a pair of knickers stuffed in his mouth. DS Jack Weston guesses he was involved in a sex game that went badly wrong and suspicion falls on Saul Hammond, the man who found him.