BIRMINGHAM, Ala. (WIAT) — An inmate serving a 15-year prison sentence at William E. Donaldson Correctional Facility in Bessemer died Thursday morning, the Jefferson County Coroner’s Office reports.

Antoine Devaugh Rudolph, 33, was found unresponsive in his cell at Donaldson at approximately 9:43 a.m. Thursday. By 10:05 a.m., he was pronounced dead.

An autopsy was performed Friday, but the cause of Rudolph’s death has yet to be determined. The Alabama Department of Corrections is investigating the circumstances surrounding Rudolph’s death.

Rudolph was serving a 15-year sentence following his 2015 robbery conviction out of Tuscaloosa County.