Aerial images from Oklahoma City television station KWTV/KOTV showed police tape covering part of the parking lot as first responders combed through the area.
Police are interviewing witnesses and looking to see if there is any surveillance video of what happened. No other details surrounding the gunman's death have been released.
Police officials in Duncan, Okla., are responding to reports of a shooting at a local Walmart on Monday morning. Several emergency vehicles were in the parking lot. Red River Tech remains on lockdown; however, Duncan Public Schools are no longer on lockdown.
Jameis Winston suffered sprained ankle in Bucs' loss
Winston passed for 313 yards and two touchdowns in the loss, but turnovers were his downfall as has often been the case. Just three field goals last week, the Saints bounced back and put 34 points on the board in their Week 11 victory.