Richard Gonzales Samayoa
Richard Gonzales Samayoa. California Department of Corrections and Rehabilitation photo

A prison inmate on death row for fatally bludgeoning a neighbor and her toddler daughter during a burglary in Otay Mesa 37 years ago was found dead Wednesday in his cell.

Richard Gonzales Samayoa, 69, was pronounced dead at San Quentin State Prison about 1:15 a.m., according to the California Department of Corrections and Rehabilitation. His cause of death was not immediately clear, the state agency reported.

Samayoa was sentenced to death in San Diego County on June 28, 1988, for two counts of first-degree murder in the killings of Nelia Silva, 33, and her 2-year-old child, Katherine.

On Dec. 18, 1985, Samayoa fatally beat Silva and the girl, who lived across the street from him, with a wrench when they returned from an outing to find him ransacking their Piedra Street home, looking for valuables to steal, according to police and prosecutors.

The Coroner Division of the Marin County Sheriff’s Office will determine his cause of death, according to CDCR public affairs.

City News Service contributed to this article.