DENVER — A man who acknowledged that he fatally slashed a correctional officer and tried to kill a second officer in a 2012 prison rampage has pleaded not guilty by reason of insanity.

The Denver Post reports that Miguel Alonso Contreras-Perez, a convicted child rapist, entered his plea on Wednesday. He is accused of killing Sgt. Mary Ricard in the kitchen at the Arkansas Valley Correctional Facility in Ordway and stabbing Sgt. Lori Gann the same day.

Crowley County District Attorney Jim Bullock has previously announced he is seeking the death penalty against Contreras-Perez.

Perez is an Army deserter who was sentenced in 2004 to 35 years to life in prison after he kidnapped and raped a 14-year-old girl in Colorado Springs.

Information from: The Denver Post,