DURHAM, N.C. (AP) — An inmate has been found dead in his North Carolina jail cell.

The Durham County Sheriff's Office said in a news release that the 40-year-old man was found unresponsive in his cell Sunday evening.

Officials say the preliminary investigation indicates the man died of natural causes. His name has not yet been released.

The State Medical Examiner plans to perform an autopsy to determine how the man died.