Jun. 26—A guard at the Penitentiary of New Mexico outside Santa Fe was stabbed in the back of the head by an inmate earlier this month, according to criminal charges filed this week.

Cain Esquivel, a 36-year-old prisoner at the facility, faces a charge of aggravated battery with a deadly weapon from the June 12 incident, according to a statement of probable cause.

New Mexico State Police wrote in the statement Esquivel stabbed corrections officer Eric Lozano with a “shank” while the officer was conducting a “shakedown” of Esquivel’s cell.

Lozano was treated at the prison’s medical unit and received three stitches for the wound, the statement says.

Lozano and another officer had handcuffed Esquivel behind his back through an opening on the inmate’s cell called a “food port,” surveillance video shows, according to investigators, but Esquivel slipped his right hand free from the handcuffs and attacked Lozano, swinging his arms “like a hook” at the officer.

Lozano told investigators after the officers struggled to subdue Esquivel, he saw the shank and felt blood on his face.

State police spokesman Officer Wilson Silver said the weapon appeared to be made out of “wood, tape, string and a piece of metal,” and officers did not know how Esquivel obtained the weapon.