This happened in 2013:
A form of cancer killed the serial killer known as the Night Stalker who terrorized Southern California in the mid-1980s, coroner’s officials said Monday.
Richard Ramirez died June 7 at age 53 at a hospital where he had been taken for treatment of liver failure.
He really did serve life in prison and died of cancer. Of course, what with it being California, it isn’t out of the realm of possibility that he could have made parole.