The suspect in the Oklahoma airport shooting has been found dead in the back of a ute in the airport carpark.
Police believe he shot himself in the head.
Officers understand the suspect, who hasn't been identified yet, gunned down Michael Winchester, 52, while he was working at the airport.
Police Captain Paco Balderrama believes the shooting was a premeditated attack.
Oklahoma City Airport has since reopened after being closed for several hours following the fatal shooting.
Captain Balderrama said: "It's possible the shooter and the victim knew each other".
"It's also possible the shots came from the back of a truck.
Michael Winchester was working for Southwest Airlines when he was fatally shot.
A spokesperson for Southwest Airlines said: "It is with great sorrow that Southwest Airlines confirms that a Southwest Employee who was injured during a shooting incident today at Will Rogers World Airport in Oklahoma City has died from injuries".
"We continue to work with the local authorities investigating this incident.
"The Southwest Airlines family is deeply saddened by the passing of our Southwest Family Member, and we extend our heartfelt sympathies and support to his family and Southwest co-workers at this time."
There are reports the FBI was called in to help with the operation.