LINCOLN, Neb. (AP) — Nebraska prison officials say a man serving life in prison has died following a long-term medical condition.

68-year-old Michael Juranek died Wednesday night at a Lincoln hospital. Prison officials say he had been treated for an illness at the Nebraska State Penitentiary. Officials did not reveal the nature of the illness.

Juranek was serving a life sentence for first-degree murder and additional time for a weapons count in the 2011 stabbing death of his 52-year-old roommate, Jimmy McBride, in south Omaha.

Juranek’s cause of death has not been determined. State law requires a grand jury investigation anytime someone dies in state custody.