A convicted murderer was killed this week in an assault by other inmates at a Southern California prison, authorities said.
Staff at Calipatria State Prison in Imperial County witnessed Alberto Martinez, 46, being beaten in the prison yard Thursday, authorities said.
Inmate Tyler A. Lua punched him, knocked him to the ground and continued to beat 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 a baton,” the department said.
The department said Martinez had “injuries consistent with an inmate-made weapon,” and two such weapons were found where the attack occurred.
Medical personnel attempted to treat Martinez’s injuries, but he died within an hour. Jail 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 abducting 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 detailing how members of the prison-based crime syndicate use smuggled mobile phones to collect money and order murders on the city streets.
Although Martinez was initially on death row, he was among the condemned inmates moved to the general population after Gov. Gavin Newsom imposed a moratorium on executions during 2019.
According to the Department of Corrections, Martinez was also serving a life sentence for attempted first-degree murder, as well as an additional two years in prison for gang activity.
The three inmates involved were “placed in restricted housing” pending an investigation, the department said.
Lua and Negrete-Larios are both serving sentences for attempted second-degree murder and other convictions. Beltran was sentenced in 2023 to life in prison for first-degree murder.