Death row inmate Richard Allen Benson was found dead in his cell at San Quentin State Prison on Monday, according to the California Department of Corrections and Rehabilitation (CDCR).
Officials say Benson, 74, did not have a cellmate and foul play is not suspected in his death, the cause of which will be determined by the Marin County Coroner.
In 1987, Benson was sentenced to death for four counts of first-degree murder for the 1986 deaths of Laura Camargo and her three children.
Benson raped and beat Laura and suffocated her two-year-old son, then spent 30 hours sexually assaulting her two young daughters before also beating them to death and setting the family's Nipomo house on fire.
According to CDCR, there are currently 703 people on California's death row. However, in 2019, Gov. Gavin Newsom signed an executive order that put a moratorium on the death penalty in California.
