Inmate pleads guilty to murder for killing cellmate at Northern California prison
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- Alexander Mateuz pleaded guilty to murder for killing cellmate Robert Aranda.
- An Amador Superior Court judge sentenced Mateuz to 25 years to life in prison.
- CDCR officials have said Aranda was found with stab wounds and pronounced dead.
An inmate already serving a potential life sentence for a Los Angeles County shooting pleaded guilty to first-degree murder for killing his cellmate three years ago at a Northern California prison.
Alexander Mateuz, 42, the inmate at Mule Creek State Prison in Ione, entered his guilty plea last Thursday for the attack that killed his cellmate 23-year-old Robert Aranda, Amador County District Attorney Todd Riebe announced in a news release.
Following a victim impact statement last week in court by Aranda’s mother, Amador Superior Court Judge J.S. Hermanson sentenced Mateuz to 25 years to life in prison for Aranda’s death. Riebe said Mateuz will serve his sentence for the prison murder consecutively to the prison sentence he was already serving.
“No one deserves to come to violent harm in Amador County, and no one gets a pass simply because of whom they choose to victimize,” Riebe said in the news release. “This defendant is unable to be rehabilitated and live peaceably in the community. He should remain in prison for the rest of his days and should never be paroled.”
The homicide investigation began Feb. 2, 2023, after Aranda was found with several injuries, including stab wounds, in his cell at the prison in Amador County, according to the California Department of Corrections and Rehabilitation.
CDCR officials have said prison staff performed life-saving measures on Aranda and took him to the prison’s Treatment and Triage Area. He was pronounced dead about 30 minutes later.
Mateuz was identified as the alleged attacker in Aranda’s death, according to CDCR. Mateuz was moved to the prison’s administrative segregation unit while the homicide was investigated.
After the deadly attack on Aranda, Mateuz admitted to others what he had done, prosecutors said.
Aranda in November 2021 was convicted of two counts of second-degree attempted murder with the use of a gun in Los Angeles County and sentenced to 13 years in prison, CDCR officials have said.
Mateuz was serving a sentence of life in prison with a chance of parole after an August 2008 Los Angeles County conviction of assault with a firearm as a third-striker, use of a firearm and an enhancement of a street gang act in the commission of a violent felony, according to CDCR.
Prosecutors said Mateuz had also been convicted in two criminal cases for trafficking drugs into High Desert State Prison in Susanville. As of Wednesday, Mateuz was incarcerated at Kern Valley State Prison in Delano.
