Convicted killer beaten to death by three other inmates in California prison, cops say - Alberto Martinez, 46, was knocked to the ground and beaten by three inmates in the prison yard at Calipatria State Prison in Imperial County on Thursday,

Alberto Martinez, a convicted murderer who was involved in the Mexican Mafia, was attacked and killed by three inmates at Calipatria State Prison.

A homicide investigation is underway into the death of an inmate found unresponsive in his cell at Salinas Valley State Prison in Monterey County, officials announced Tuesday. California Department of Corrections and Rehabilitation officers were conducting security rounds when they made the discovery at 10:45 a.

A condemned inmate at a Southern California prison was beaten to death by three other inmates this week, the California Department of Corrections and Rehabilitation said. According to a CDCR

The Bay Area man was killed last week in a California prison where he'd been serving a life sentence for murdering a close friend, officials said.

A mafia member on death row was beaten to death by three other inmates at a prison in Southern California, officials said. No staff or other inmates were injured.

Alberto Martinez was the getaway driver for the 2002 abduction and slaying of Buena Park businessman David Montemayor.