State prison officials are investigating the death of inmate John Cisneros as a homicide at California State Prison Sacramento; his cellmate has been detained.

FOLSOM, Calif. — Officials are investigating the death of an incarcerated man at California State Prison, Sacramento as a homicide.

Around 9:15 p.m. on Feb. 23, 2026, staff found 49-year-old inmate John Cisneros unresponsive in his cell. Despite efforts to save his life, Cisneros was pronounced dead at 9:59 p.m.

His cellmate, 34-year-old Irvin Sanchez, was removed from the cell and placed in restricted housing while the Sacramento County District Attorney’s Office and the prison’s investigative unit review the incident. The Office of the Inspector General has been notified.

Cisneros was received from Los Angeles County in 2015 and was serving time for robbery and additional sex crimes convictions received while incarcerated. 

Sanchez was received in 2013 and is serving time for attempted second-degree murder and firearm-related offenses.

The investigation into Cisneros’ death is ongoing, and authorities have not released further details.

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