The dark story of Britain's most infamous child murders, including never-before-seen prison letters. Why do serial killers Ian Brady and Myra Hindley continue to haunt us as embodiments of pure evil?
The Witness: An eyewitness to a killing alerts the police to a series of gruesome child murders
The Lost Letters: A horrific tape recording and photos lead to a search on the moors, revealing more victims
The Trial: Brady and Hindley are brought to court. Letters reveal details of their lives in prison.