LINCOLN, Neb. (AP) — Authorities say an inmate at Nebraska State Penitentiary has died following a medical emergency at the prison.

60-year-old Rolland Jones died Friday after experiencing a medical emergency and being taken by ambulance to Bryan East Medical Center in Lincoln, where he died overnight.

Jones had been incarcerated since Feb. 6, 2004, and was serving a 27- to 40-year sentence for first-degree assault and use of a deadly weapon to commit a felony. Authorities say the cause of his death has not yet been determined.

As required by state law anytime someone dies in custody, a grand jury will investigate the death.