LITTLE ROCK, Ark. (AP) — Authorities are investigating the fatal prison assault of a convicted murderer who died last week.

The state Division of Correction said Jerry Richard died at a Little Rock hospital on Friday, two days after the assault at the Cummins Unit. Richard, who was 55, was serving a life sentence for a first-degree murder conviction out of Washington County.

The Department of Corrections began an internal investigation following Richard’s death, and Arkansas State Police are also investigating his death.

A State Police spokesman said the agency was notified about the inmate’s death on Monday.