FAIR GROVE, Mo. (AP) – A southwest Missouri man has pleaded guilty in the shooting death of his girlfriend in 2016.

As part of a plea deal, 40-year-old Carlton Wallace was expected to spend 20 years in prison for the death of 26-year-old Lindsay Arnold in February 2016 in Fair Grove.

The Springfield News-Leader reports Wallace’s mother called sheriff’s deputies after her son would not let her enter an outbuilding where he lived with Arnold. He was arrested at a Walmart in Springfield hours after the killing.

Deputies found Arnold dead under a blanket with red foam around her mouth and a gunshot wound to the back of her head.

Wallace’s mother told police Wallace and Arnold had an extensive history of domestic violence and authorities came to the property numerous times.