John Bingham, 17th Earl of Lucan
In 1974, Lord Lucan (who was once considered for the role of James Bond) got fed up with battling his wife for custody of their three children, and with spying on them and recording their telephone conversations, and decided to simply bludgeon her to death in a darkened room. The problem with committing murder in a darkened room, though, is that you can’t verify your target. So instead of killing his hated wife, he ended up killing his children’s dearly beloved nanny, Sandra Rivett. Whoops.
After the murder, he vanished, and was never found. Some say he disappeared to Africa and died in the wilderness, some say he jumped into a river, and some say that his friends fed his remains to tigers at a private zoo. No matter which way you slice it, though, this guy probably met the end he deserved.