DELANO, Calif. (AP) — The death of a 50-year-old inmate at a Southern California prison is being investigated as a homicide, authorities said Sunday.

Alfredo Valenzuela was found unresponsive Saturday in his cell at Kern Valley State Prison, the state Department of Corrections and Rehabilitation said in a statement. He was pronounced dead a short time later.

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Valenzuela’s cellmate, 36-year-old Noe Herrera, was moved to the prison’s Administrative Segregation Unit pending investigation, the statement said.

The Kern County Coroner’s Office will determine Valenzuela’s official cause of death.

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Valenzuela entered Kern Valley prison in 2010 on a life-without-parole sentence after being convicted of murder and other charges.

Herrera, also convicted of murder, was sentenced to life without parole in 2019.

Kern Valley houses more than 3,200 inmates in minimum-, medium-, and high-security lockups.

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