PEARL, Miss. (AP) — A spokeswoman for the Mississippi Department of Corrections says a prison inmate has been found unresponsive in his cell.

Spokeswoman Grace Simmons Fisher said 20-year-old Darrell Harper was found unresponsive Tuesday at the Central Mississippi Correctional Facility near Pearl. Harper was serving a 5-year prison sentence for residential burglary.

Harper’s death is the first known death in the state prison system since 16 inmates died in August. Corrections Commissioner Pelicia Hall said then that she believed most of the deaths were from natural causes including cancer and heart disease. She also asked the state and FBI to investigate.

Rankin County Coroner David Ruth says Harper’s body has been taken to the medical examiner’s office. He says Harper’s cause of death is pending an autopsy.