SAN JOSE (CBS SF) — Staff at the Santa Clara County Main Jail discovered one of its inmates was unresponsive Saturday evening and transported him to a local hospital, where doctors declared him dead within an hour, the county sheriff’s office said.

Deputies discovered the unresponsive inmate at 7 p.m. Saturday during a routine welfare check, the Santa Clara County Sheriff’s office said. Deputies and jail medical staff performed CPR and other life-saving measures before the San Jose Fire Department and paramedics arrived to transport him to the hospital, where he was pronounced dead at 7:42 p.m.

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The 52-year-old man was booked into custody on Dec. 27 for charges of criminal threats, a violation of a court order and a violation of a restraining order, the sheriff’s office said.

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“The Sheriff’s Office is following standard protocol for an in-custody death that includes, but is not limited to; joint investigation between Sheriff’s Office investigators and District Attorney’s investigators, as well as the Medical Examiner Coroner’s Office,” the sheriff’s office said in a statement. “Based on our preliminary investigation, there were no signs of foul play and the man was housed alone at the time of the incident.”

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