BIG STONE GAP, Va. (WRIC) — An inmate was killed in custody Sunday in what Virginia prison authorities believe was an attack by a fellow inmate.

The Virginia Department of corrections announced that an inmate was found unresponsive Sunday afternoon at Wallens Ridge State Prison, after he was apparently attacked by another inmate.

The prison has been the site of several incidents of inmate violence, and the latest killing will be investigated by the Department of Correction’s Special Investigations Unit.