Couples Who Kill explores for the first time the bizarre and macabre phenomenon of murder committed by two individuals possessed of a single evil impulse. Obsessed and sucked into a private world of madness, their attraction is always fatal - to someone else. Meet: - Pauline Parker and Juliet Hulme, the lesbian schoolgirls who cold-bloodedly beat Pauline's mother to death - Leopold and Loeb, the clever sons of wealthy Chicago businessmen who methodically planned the kidnapping and murder of a fourteen-year-old boy, a murder without a motive - Bonnie and Clyde, Hollywood didn't dare reveal the whole sordid truth about the small-time, but deadly, desperadoes - Brady and Hindley, their crime was described by Justice Sparrow as the 'cruellest and most horrific crime of perverted passion this century' .