DENVER — A 23-year-old man who was arrested in Wyoming after police say he confessed to killing his girlfriend in their suburban Denver apartment has pleaded guilty to second-degree murder.

Jonathan Akin entered his plea Wednesday in the Nov. 25, 2018, stabbing death of 21-year-old Autumn Rivera and faces 25 to 40 years in prison as part of a deal with prosecutors. He is scheduled to be sentenced April 28.

Authorities say Akin surrendered to police in Powell, Wyoming, and officers found Rivera dead in the trunk of his car.

According to an arrest warrant, Akin told investigators he killed Rivera in Thornton but did not remember how because he had “blacked out.” He then drove to his mother’s home in Wyoming.