Abstract
Psychiatrists define folie a deux as communicated insanity; a rare psychotic disorder that may be transmitted from the sufferer to a person or persons closely related to him/her. The disorder is often described in the context of schizophrenia, but different varieties of folie a deux have been noted in other conditions. In criminology, the term is used in the framework of team killers and seldom involves false or delusional beliefs, but rather deviant behaviour shared by two. Examples of notorious folie a deux unions include Ian Brady and Myra Hindley, Fred and Rosemary West, Charles Ng and Leonard Lake, and Angelo Buono and Kenneth Bianchi. In fiction, folie a deux with a criminal intent appears in Truman Capote's In Cold Blood (1966), where a dominant leader unites with a passive follower to commit felonies. The novel, based on the real-life massacre of the Clutter family in Holcomb, Kansas in 1959, centres on the two men responsible for the carnage, Richard Eugene Hickock and Perry Edward Smith. Capote introduces the process that brings these two warped individuals together, the early stages of their friendship, their personalities, why they are attracted to each other, and how, over time, their relationship becomes more sinister. By exposing the inner workings of their criminal minds the author enters the domain of criminologists and psychologists who are only now beginning to understand the true dynamics behind couples that kill.