(AP) — A 15-year-old Wyoming boy charged with killing a Nebraska jail guard has pleaded guilty to the crime that originally led to his jailing.

On Friday Dylan Cardeilhac pleaded guilty to robbery in Scotts Bluff County District Court in Gering. His sentencing is scheduled for May 22. Prosecutors say Cardeilhac and a 14-year-old in December robbed a convenience store in Mitchell. The other boy has not been caught.

Cardeilhac has pleaded not guilty to a murder charge in the slaying of 24-year-old Amanda Baker on Feb. 14. Authorities say he lured Baker into his jail cell and then pounced on her, strangling her from behind.