On the 9th of November 1971 bank worker John List systematically murdered his wife, mother, and three children with a pair of handguns. He then proceeded to clean and tidy the family home, cut himself out of every photograph in the house with a pair of scissors, tune the radio to a religious station and walk away from his life forever. It would be decades before this murderer was found, and longer still before we achieved any kind of understanding as to why he committed such senseless and terrible crimes.