OKLAHOMA CITY (AP) - A man charged with beheading a co-worker with a butcher knife at an Oklahoma food processing plant is scheduled to formally enter a plea to first-degree murder.

Alton Nolen is set to be arraigned in a Cleveland County courtroom Thursday for the September 2014 attack at the Vaughan Foods plant in the Oklahoma City suburb of Moore. The 31-year-old Nolen has entered an initial plea of not guilty.