An investigation into the case of doorman and car clamper Levi Bellfield, who committed three murders - including that of schoolgirl Milly Dowler in 2002. But would he have gone on to claim even more victims had he not made a string of mistakes that alerted police? Interviews with detectives, including the officer who interrogated Bellfield, as well as a former partner of the murderer, reveal the errors that led to his arrest.

The errors made by Mick Philpott that led to his arrest for causing the death of five of his children and their half-brother by setting light to his home in Derby. The programme examines how his unconvincing appearance at a press conference and ill-timed attendance of a karaoke party raised the police's suspicions - leading them to bug his hotel room and hear an incriminating conversation.