Inmate beaten and killed by other inmates in California prison

A convicted murderer was killed this week in an attack by other inmates at a Southern California prison, authorities said.

Staff at Calipatria State Prison in Imperial County witnessed the death of 46-year-old Alberto Martinez on prison grounds Thursday, authorities said.

Inmate Tyler A. Lua punched him, knocked him to the ground and continued to hit him, the California Department of Corrections and Rehabilitation said in a news release.

Two other inmates, Jorge D. Negrete-Larios and Luis J. Beltran, began beating Martinez as he lay motionless, and staff “stopped the incident with pepper spray and one baton,” the department said.

The department said Martinez had “injuries consistent with a locked-up weapon,” and that two such weapons were found at the scene where the attack occurred.

Medical personnel attempted to treat Martinez’s injuries, but he died within an hour. Prison officials say they are investigating his death as a homicide.

The Imperial County Coroner will determine the exact cause of death.

Martinez had been sentenced to death in 2010 after being convicted of first-degree murder for his role in kidnapping and killing a man in exchange for payment from the man’s sister.

Martinez described himself in court as an associate of the Mexican mafia. He was featured in a 2023 Los Angeles Times article that detailed how members of the crime syndicate worked in the prison using smuggled mobile phones to raise money and order murders on the city streets.

Although Martinez was initially on death row, he was among the condemned inmates transferred to the general population after Governor Gavin Newsom. imposed a moratorium on executions in 2019.

Martinez was also serving a life sentence for attempted first-degree murder and an additional two years for street gang activity, according to the Department of Corrections.

The three inmates involved were “placed in restricted housing” pending an investigation, the department said.

Lua and Negrete-Larios are both serving prison sentences for attempted manslaughter and other convictions. Beltran was sentenced to life in prison in 2023 for first-degree murder.