SPRINGFIELD (AP) – A Springfield man will be sentenced in October for the shooting death of his girlfriend, which he at first claimed was an accident.

Twenty-eight-year-old Darrell Smith pleaded guilty Friday to second-degree murder in the death of his girlfriend, 23-year-old Kimberly Walker. Sentencing was scheduled for Oct. 23.

Smith originally pleaded not guilty and claimed a gun accidentally went off while the couple was sitting on the couch last Dec. 30. He said he thought the gun wasn’t loaded. Walker died the next day.

The medical examiner and investigators said evidence showed that version of events wasn’t possible.