SIOUX FALLS, S.D. (KELO) -- Mark N. Peters, who was convicted of killing his wife Carol Jean Peters in 1990, has died in prison. The South Dakota Department of Corrections said Peters, 67, died on Thursday. The state did not list a cause of death. 2 Huron teens sentenced to 25 years for murder Peters was sentenced to life in prison for first-degree murder in Minnehaha County. Peters pleaded guilty to killing his wife. The death also involved a stand-off with Sioux Falls Police that lasted several hours. Peters is the 12th inmate to die in state prison this year.