McALESTER, Oklahoma - The Department of Corrections says an investigation is underway after an inmate was pronounced dead in his cell Monday. 

According to the report, around 4 p.m. Monday, November 25 a correctional officer found Albert Johnson unresponsive in his single-cell unit at the Oklahoma State Penitentiary in McAlester, Oklahoma.

DOC says Johnson was pronounced dead shortly after he was discovered.

Johnson was serving a death sentence for a first-degree murder conviction, and life sentences for shooting with intent to kill, forcible sodomy, first-degree rape, kidnapping and, assault and battery with a dangerous weapon.

The Oklahoma Medical Examiner’s Office will determine Johnson’s exact cause of death.