STOCKTON (CBS13) – An investigation is underway after an inmate at the San Joaquin County Jail died over the weekend.

The San Joaquin County Sheriff’s Office says correctional officers found the 44-year-old man unresponsive in his single-person jail cell. Other staff and medics were immediately called for help, authorities say.

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Life-saving measures were started by officers until medics took over, but the man was soon pronounced dead at the scene.

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The name of the inmate has not been released at this point, but the sheriff’s office says he had been in custody since Dec. 5 on two misdemeanor warrants. He was set to be released from custody on Dec. 29.

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An investigation is now pending to determine the man’s cause of death.