A 49-year-old inmate serving a 28-year sentence for sexual assault was found dead inside his cell at California State Prison, Sacramento on Sunday evening, and his cellmate has been detained as authorities investigate what they are calling a homicide.
John Cisneros was discovered unresponsive in his cell at approximately 9:15 p.m. on February 23, according to the California Department of Corrections and Rehabilitation. Correctional officers and medical staff responded immediately, but Cisneros was pronounced dead just before 10 p.m. that same evening.
Cellmate Detained, Placed in Restricted Housing
Irvin Sanchez, 34, who shared the cell with Cisneros, has been detained and placed in restricted housing while investigators work to determine the circumstances of the death. Sanchez is currently serving an 18-year sentence for attempted second-degree murder with gang and gun enhancements — a violent history that investigators will likely scrutinize as they build their case.
Four separate agencies are now involved in the investigation: the prison’s own Investigative Services Unit, the Sacramento County District Attorney’s Office, the Office of the Inspector General, and the Sacramento County Coroner’s Office. Final reports on the cause and manner of death are expected within six months.
A Facility Under Pressure
California State Prison, Sacramento — known as SAC or New Folsom — sits in Represa, just outside Folsom, and houses more than 2,200 incarcerated men across medium, maximum, and high-security levels. The facility has long been one of the state’s more volatile institutions, holding a significant population of inmates classified at the highest security levels.
The prison, which opened in 1986 as an expansion of the original Folsom State Prison, has seen multiple violent incidents over the years. Housing inmates with lengthy sentences for violent crimes — including attempted murderers alongside sex offenders, as this case illustrates — creates an inherently dangerous environment that correctional staff must manage around the clock.
Who Was John Cisneros?
Cisneros had a documented criminal history in the California prison system. In 2015, he received a five-year sentence for second-degree robbery. Then in 2017, he was sentenced to 28 years for penetration, oral copulation, and attempted rape with force, violence, and fear of immediate bodily injury — charges that would have classified him as a sex offender within the prison system.
That classification is significant. Sex offenders are among the most targeted inmates in the prison hierarchy. Despite California’s efforts to implement protective housing measures, inmates convicted of sexual crimes remain at substantially higher risk of violence from other prisoners. Studies have consistently shown that sex offenders face assault rates several times higher than the general prison population.
Prison Violence in California: A Persistent Problem
This death comes amid ongoing scrutiny of violence within California’s state prison system. According to CDCR data, in-custody deaths have remained stubbornly high even as the state’s overall prison population has declined through reforms like Proposition 57 and the ongoing prison closure program under Governor Newsom.
California has closed five state prisons since 2021 as part of a downsizing initiative, concentrating remaining inmates in fewer facilities. Critics have argued that consolidation without proportional staffing increases can exacerbate tensions and violence. The Bureau of Prisons nationally has faced similar staffing shortages that compromise safety.
Cell assignments — who shares a cell with whom — remain one of the most consequential decisions correctional administrators make daily. Pairing an inmate convicted of sex crimes with one serving time for attempted murder with gang enhancements raises questions that investigators and prison officials will need to address.
What Happens Next
The Sacramento County District Attorney’s Office will ultimately decide whether to file criminal charges against Sanchez. If charged with murder in the death of Cisneros, Sanchez could face additional years — potentially a life sentence — on top of the 18 years he is already serving.
The Office of the Inspector General’s involvement signals that the investigation will also examine whether the prison followed proper protocols regarding cell assignments and inmate classification. Their review could result in policy recommendations aimed at preventing similar incidents.
For now, California State Prison, Sacramento continues to operate as investigators piece together what happened inside that cell on Sunday night. The facility’s phone number is available on our facility detail page for anyone seeking information about an incarcerated loved one.
