WARREN, Maine — The death of a 53-year-old prisoner at the Maine State Prison does not appear to be suspicious, according to the Maine Department of Public Safety.

Stephen Ray Gravel died at 5:45 a.m. Tuesday, according to the Maine Department of Corrections.

Consistent with department policy and Maine attorney general’s office protocols, the Maine State Police and the Maine medical examiner were notified. Both are reviewing the death.

Maine Department of Public Safety spokesman Stephen McCausland said Tuesday that he has not been informed of anything suspicious about the death, pointing out that all inmate deaths are reviewed by state police. A detective has been assigned to review the case.

Scott Fish, a spokesman for the Department of Corrections, said he could not comment on whether Gravel was in his cell or the infirmary when he died or whether he had been ill recently.

Gravel had lived in Oxford before being sent to prison. He had served approximately five years of a 16-year sentence for gross sexual assault.