A corrections officer at a private prison in Oklahoma was killed by an inmate over the weekend, the Oklahoma Department of Corrections said Monday.
The attack took place at Davis Correctional Facility in Holdenville, about 77 miles east of Oklahoma City, the corrections department said in a statement.
Officer Alan Jay Hershberger died about 10 a.m. Sunday, following the attack, it said. The exact time of the violence was not revealed.
He was "conducting an inmate movement when he was attacked from behind" by an inmate with a homemade weapon, according to the statement.
NBC affiliate KFOR of Oklahoma City reported Hershberger was attacked as inmates were returning to housing from recreation.
"Davis Correctional Facility staff responded quickly and valiantly after the attack, attempting life-saving measures while securing the area to ensure the safety of staff and other inmates," the corrections department said Monday.
The alleged attacker was identified by prison officials as inmate Gregory Thompson, who they said is serving a life sentence for a 2003 first-degree murder conviction.
The inmate was also subject to forthcoming sentencing for a 2009 first-degree manslaughter case, they said.
A corrections spokesperson did not immediately answer a request to allow Thompson to respond to allegations he killed the officer.
The attack was being investigated by the corrections department's Office of the Inspector General, who will submit results to a local prosecutor for charging consideration, the department said.
The facility is owned by Tennessee-based CoreCivic, which says it's the nation's largest owner of "partnership correctional, detention and residential reentry facilities."