An inmate from San Diego County was killed earlier this week inside Kern Valley State Prison, authorities said Saturday.

According to the California Department of Corrections and Rehabilitation, Esteban Ceja, 29, and Adrian Gurrola, 31, are believed to have attacked the inmate in a common room with an “inmate-manufactured” weapon.

Hector Jimenez, 35, was killed after he was attacked in a common room at the Kern Valley State Prison on June 24, 2022 (California Department of Corrections and Rehabilitation)

The inmate, identified as 35-year-old Hector Jiminez, was seriously injured and taken to the prison’s triage center for treatment after he was attacked around 7:20 p.m. Friday.

An ambulance was called to take the inmate from the prison to the hospital, but he died before he could be transported, CDCR officials said.

Jiminez, an accused gang member, was sentenced in San Diego County in 2015 to 26 years for voluntary manslaughter with a firearm.

Both Ceja and Gurrola were serving sentences out of Los Angeles County, CDCR said.

Ceja was admitted into the California prison system in October 2018 following a conviction for second-degree murder and attempted second-degree murder. He is currently serving a life sentence with the possibility of parole and was also sentenced for an assault that happened while incarcerated.

Gurrola has been imprisoned since August 2009 for first-degree murder, two counts of attempted first-degree murder and animal cruelty charges. He also received an additional sentence while in prison for possession of a concealed knife. He is serving a life sentence with the possibility of parole.

Both Ceja and Gurrola are convicted gang members, CDCR officials said, although it’s unclear if the attack on Jimenez was gang-motivated.

The prison’s investigative unit is investigating the attack alongside the Kern County District Attorney’s Office and the county coroner. The coroner has been tasked with determining Jimenez’s cause of death.

Prison staff have limited movement on the prison yard while the facility’s investigation unit works to determine what led up to the deadly attack.

The Kern Valley State Prison is located just outside of Delano. The prison houses about 3,200 inmates in minimum, medium and high security settings.

This is the second time in the past two months that two inmates have killed a fellow inmate at the prison.

In late May, a 31-year-old man serving a sentence out of Los Angeles County died after he was attacked by two fellow inmates in a recreation yard.

Earlier that month, another inmate died after he was found seriously injured in his cell, which led to his cellmate being detained and separated from the rest of the prison population.