A 58-year-old man died early Wednesday after reportedly experiencing a medical emergency in the county jail in San Jose, according to a statement from the Santa Clara County Sheriff’s Office.

The man was booked Monday into the Santa Clara County Main Jail by the San Jose Police Department, following his arrest on a felony warrant for false imprisonment.

The sheriff's news release reported that at about 11pm Tuesday during a routine medical assessment of prisoners at the jail the man was alert and standing.

“Suddenly, he began to experience medical emergency and was assisted down to his bed,” according to the statement. “Medical staff immediately began life-saving measures.”

At about 11:46pm, the man was taken to a local hospital where he was pronounced dead at 12:36am Wednesday.

A preliminary investigation indicated there were no signs of foul play, according to the statement, which noted that the man had been housed alone in his cell.

Officials did not release the name of the man, pending notification of next of kin.

Following standard procedure, a joint investigation of the incident is under way between the sheriff's office, district attorney's office and the Santa Clara County Medical Examiner-Coroner's Office.