HOLDENVILLE, Okla. (KFOR) – Officials with the Oklahoma Department of Corrections have released more information following a deadly attack at a correctional facility.

On Sunday, officials with the Davis Correctional Facility in Holdenville announced that a correctional officer died from an injury sustained during an attack by an inmate.

“As a group of inmates were being returned to their housing area from recreation, the assailant attacked the officer,” a statement by the Oklahoma Department of Corrections said.

Immediately, crews worked to save the officer. The victim, who was identified as Alan Jay Hershberger, died from his injuries.

Investigators say Hershberger was attacked from behind, and the inmate was armed with a homemade weapon.

The attacker has been identified as Gregory Thompson, who is serving a life sentence for a 2003 murder conviction in Oklahoma County.

Thompson was also convicted of manslaughter in 2009 in Pittsburg County.