This three-part series tells the story of Britain’s most infamous child murders and 1960s serial killers Ian Brady and Myra Hindley. The series is built around never-before-seen prison letters from Brady and Hindley to the same source, written in the five decades after their capture. Expert analysis of these letters provides new insight into their backgrounds, thinking and motivation. Moors Murders also asks why both killers – especially Hindley – remain such notorious embodiments of evil. In this second episode, The Lost Letters, following the arrest of Brady for a single murder, police discovered a tape recording of a 10-year-old girl being tortured and realised they were investigating a string of child murders – with Hindley also implicated. Eyewitness Clive Entwistle describes the first police search of the moors above Manchester. He was present when the remains of the girl on the tape were found. He explains how police used photographs of the serial-killing couple posing on the moors to locate the body of the third known victim, a 12-year-old boy. Janie Jones conducted a 40-year-long correspondence with both Hindley and Brady. Exclusive access to the letters provides a wealth of new material on Brady’s Glasgow childhood and how his macabre obsession with graveyards later manifested itself in the secret cemetery he and Hindley created on the moors. The film also covers why, 20 years later, Brady and Hindley confessed to two further murders, leading to the discovery, in 1987, of the remains of their first victim; and the fruitless search for the last undiscovered child.