SACRAMENTO, Calif. (AP/CBS13) — A California man sentenced to death for the 1995 torture slaying of an Orange County teenager died early Monday of unknown causes, prison officials said.

Noel Jesse Plata, 45, was found unresponsive in his cell at San Quentin State Prison before 4 a.m. and pronounced dead about a half-hour later despite the employee’s attempt at life-saving measures and outside medical assistance, they said.

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Officials do not suspect foul play, but Plata’s death will be investigated, officials said. The cause of death will be determined by a coroner.

He and an accomplice, Ronald Tri Tran, were sentenced to death for the first-degree murder of Linda Park, 18. The two gang members tortured her into revealing where her family kept its valuables, then strangled her.

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Plata was already in prison serving a sentence of life with the possibility of parole for another first-degree murder when he was convicted in Park’s slaying.

There are currently 710 people on California’s death row, the nation’s largest, though Gov. Gavin Newsom has imposed a moratorium on executions so long as he is governor.

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