A man who died in County Jail Monday morning has been identified as a 57-year-old San Francisco resident, according to the San Francisco Sheriff's Department.
Alvin Haynes died for unknown reasons at 10:30 a.m. in Jail 5 in San Bruno Monday morning, the Sheriff's Department said.
Chief Deputy Kathy Gorwood, a spokesperson for the department, said the details of the incident could not be released since it remains under investigation.
The San Mateo County Sheriff's Department, Medical Examiner's Office, as well as the county District Attorney's Office are among the investigating agencies.
Haynes was booked into jail in July 2012 for multiple charges, including felony second degree burglary. He was also on probation for possession of a controlled substance and possessing stolen property.
He had been sentenced on his probation violation but was awaiting trial on his other charges.
Last year, two inmates died in custody in county jails, according to the Sheriff's Department.