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, California Department of Corrections and Rehabilitation said

Alberto Martinez, 46 (pictured in mugshot), was behind bars in Calipatria State Prison for first-degree murder (California Department of Corrections and Rehabilitation)

A convicted killer was brutally beaten to death by three other inmates inside a California prison, according to authorities.

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, California Department of Corrections and Rehabilitation said in a press release on Friday.

The attack unfolded at around 1.23pm when officials allege that Tyler Lua, 25, struck Martinez, knocking him to the ground and repeatedly striking him.

Officials allege that the two other inmates Jorge Negrete-Larios, 33, and Luis Beltran, 31, then began striking Martinez “as he lay motionless.”

Staff reportedly broke up the altercation using pepper spray and a baton and performed life-saving measures on the 46-year-old.

He was rushed to the prison’s urgent care treatment area before being pronounced dead around an hour later. A coroner will determine his official cause of death.

No other staff or prisoners were injured in the incident.

Prison officials said “two incarcerated-manufactured weapons” were discovered at the scene.

One of the accused Tyler A. Lua, 25, (pictured in mugshot), currently serving a 19 year sentence for attempted second-degree murder (California Department of Corrections and Rehabilitation)

The motive for the attack remains unknown.

The three suspects have now been placed in “restricted housing pending an investigation,” the CDCR said.

Martinez had been held at the facility since 2014, after being sentenced to death for first-degree murder. He was also sentenced to life with the possibility of parole for attempted first-degree murder with an enhancement for street gang activity and two years for street gang activity.

Martinez was convicted of conspiracy to commit murder and street terrorism in the killing of Orange County businessman David Montemayor in 2002, according to The Orange County Register. During his trial, jurors heard how Martinez and three other gang members were recruited by the victim’s sister to kidnap and kill him.

Jorge Negrete-Larios (pictured in mugshot), 33, is serving a 32 year, four-month sentence for attempted second-degree murder (California Department of Corrections and Rehabilitation)

Despite being initially sent to death row, Martinez was moved to general population after California Governor Gavin Newsom issued a moratorium on executions in 2019.

Lua, who had been behind bars at Calipatria State Prison since 2019, is serving a 19-year sentence for attempted second-degree murder with an enhancement for use of a firearm. He is also serving a two-year sentence for possession of a controlled substance while in prison.

Negrete-Larios is serving a 32-year, four-month sentence for attempted second-degree murder with enhancements for inflicting great bodily injury, discharge of a firearm, and street gang activity in commission of a violent felony.

Luis Beltran (pictured in mugshot), 31, is serving life without parole for first-degree murder (California Department of Corrections and Rehabilitation)

The third suspect – Beltran – is serving life without parole for first-degree murder with enhancements for intentional discharge of a firearm causing great bodily injury/death; as well as possessing/owning a firearm as a felon.

Martinez’s death comes four years after another inmate died at the prison after being allegedly attacked by fellow inmates. Joseph Martinez, 21 – who was serving 24 years to life for attempted first-degree murder – was fatally stabbed in the chest and back in February 2020.

Calipatria State Prison is home to at least 2,638 minimum and maximum security prisoners, according to California prison authorities.