A condemned inmate at San Quentin State Prison was found unresponsive and pronounced dead early Thursday morning, according to the California Department of Corrections and Rehabilitation.
Sam Brasure was discovered in his cell around 12:50 a.m. and pronounced dead at 1:17 a.m.
Investigators say his cause of death is not yet being released, pending the results of an autopsy.
Brasure, 49, had been on death row since 1998. He was convicted of first-degree murder in the case of 20-year-old Anthony Guest in Ventura County.
Prison officials say Brasure kidnapped and tortured the former child actor, then set him on fire.
There are 731 individuals on death row in California, according to the state. Since 1978, 82 condemned inmates have died of natural causes, 27 have died by suicide and 15 have been executed, although two of those individuals were executed out of state.