James Lewis, the prime suspect in the 1982 Tylenol murders, was found dead in his Cambridge, Massachusetts home on Sunday. Lewis had served more than 12 years in prison for an extortion letter demanding $1 million from Johnson & Johnson and its subsidiary, the maker of Tylenol. His death marks the end of a 38-year investigation into the Tylenol murders, which remain unsolved and the motive behind them a mystery.