BESSEMER, Ala. (WIAT) — An inmate at William E. Donaldson Correctional Facility was found dead on his bed Monday morning.

Matthew Wade Mork, 33, was found lying unresponsive on his bed in the prison infirmary at 5:48 a.m., according to the Jefferson County Coroner’s Office. Officials say Mork, who was serving a life sentence at Donaldson for a 2010 sodomy and sexual abuse conviction out of Cullman County, was being treated at the infirmary for an unspecified “significant natural disease.”

An autopsy will be performed on Tuesday to determine how Mork died. The Alabama Department of Corrections is investigating the circumstances surrounding his death.

Mork’s death marks the second inmate dead in less than a week at Donaldson. Mitchell Cosby, 41, was killed in an assault at the prison June 15.