California Department of Corrections and Rehabilitation spokeswoman Terry Thornton said that Larry Graham, 58, was found unresponsive in his cell at San Quentin State Prison shortly after 6 a.m. and was pronounced dead at 6:45 a.m.
Graham was convicted in Contra Costa County Superior Court in 2002 and sentenced to death in 2003 for the murder, rape and sodomy of Angela Bugay, who was abducted from the Antioch apartment complex where her family lived on Nov. 19, 1983. Graham lived in the same complex at the time.
The girl's nude body was found a week later in a shallow grave near the Contra Loma Reservoir south of Antioch. She had been strangled.
Thornton said she could give no details of the Graham's death other than to confirm it is being investigated as a suicide.
Thornton said there are 683 other inmates on death row, with cases in various stages of appeal. Graham's appeal had not yet been heard by the California Supreme Court, the first step in the death penalty appeals process.
The spokeswoman said Graham would be the 17th death row inmate to have committed suicide since California reinstated the death penalty in 1978.
Graham, who had briefly dated the victim's mother, was a suspect in the murder but was not arrested until 1996, when DNA tests linked him to the case.
Graham, a former commercial pilot, was managing an auto repair shop in Concord and had recently moved to the city when he was arrested in 1996.