ORDWAY, Colo. (CBS4) – A guard killed inside prison walls may have been targeted by an inmate who knew her from years ago.

Sgt. Mary Ricard was stabbed and beaten earlier this week while supervising the preparation of breakfast for inmates at the Arkansas Valley Correctional Facility in Ordway.

The suspect is Miguel Contreras-Perez, and several years ago he did time in the Buena Vista Correctional Facility. He worked in the food service at the same time Ricard was working there.

In the attack at Ordway Contreras-Perez also went after and critically injured another guard — Sgt. Lori Gann.

The prison remained on lockdown Wednesday night.

There will be a public memorial service for Ricard Monday morning at Crowley High School.

Mary Ricard, left (credit: Department of Corrections) Arkansas Valley Correctional Facility, right (credit: CBS)