The vast majority of killers prey on their victims alone and undercover. But in a tiny number of cases, two people are drawn together to form a deadly duo
S01:E01 - Season 1, Episode 1
Mark Billingham uncovers the story behind Britain's infamous murderers, Myra Hindley and Ian Brady.
S01:E02 - Season 1, Episode 2
John Duffy and David Mulcahy are the most prolific rapists in UK history who turned to murder.
S01:E03 - Season 1, Episode 3
Mark Billingham reveals crimes committed by a flamboyant fake butler and his apprentice.
S01:E04 - Season 1, Episode 4
Wannabe Bonnie & Clyde duo, Lee Whiteley and Debbie Taylor, began an orgy of crime, sex, and murder.