(AP) — A 15-year-old Wyoming boy has pleaded not guilty to murder in the strangling of a western Nebraska jail guard.

Dylan Cardeilhac, of Torrington, Wyo., made his plea Monday in Scotts Bluff County District Court. Authorities say security video shows Cardeilhac luring 24-year-old Amanda Baker into his cell on Feb. 14 and shows him pouncing on her and strangling her from behind.

Authorities say another inmate, 16-year-old Guy Eagle Elk, of Lisco, told Cardeilhac how to choke the woman. Eagle Elk’s trial on a charge of aiding and abetting assault is scheduled for July. He’s pleaded not guilty.

Both boys are charged as adults.