William Carlson, 18, went to prison for 90 years Tuesday for killing his parents while a psychiatrist who has been treating the youth speculated he had been physically and sexually abused as a child.

On Oct. 24, 1990, William “Willie” Carlson, 16, rented a handgun for $100 from fellow students at Warren Township High School in Gurnee, said Chief Deputy State’s Atty. Jeff Pavletic.