He confessed to killing 3 other inmates months ago. The DOC just referred charges for the slayings.

He confessed to killing 3 other inmates months ago. The DOC just referred charges for the slayings.

Photo by Alex Potemkin | Getty ImagesIt was hardly a whodunnit: Ricky Wassenaar killed three other prisoners at a state prison in Tucson in April, and he claimed to have killed a fourth last November. He had reportedly told prison officials and a prison advocate outside the system that he was going to kill anyone they put in his cell. Not only were some of the murders most likely caught on surveillance video, Wassenaar also confessed to all four…