OKLAHOMA CITY -- Police say the man accused of fatall/y shooting an Oklahoma City airport employee used to work for Southwest Airlines and that the attack was likely in retaliation for circumstances that led to the attacker's 2015 resignation.

Capt. Paco Balderrama identified the shooter as 45-year-old Lloyd Dean Buie, of Oklahoma City.

He says Buie resigned from Southwest Airlines in April 2015 and that investigators believe he shot and killed 52-year-old Michael Winchester on Tuesday in retaliation for circumstances that led to Buie leaving the job.

Balderrama says he doesn't know what Buie did for Southwest or why he resigned. He says Winchester was not Buie's immediate supervisor.

Winchester was shot as he walked to his car after leaving work.

Buie was found dead of a self-inflicted gunshot wound to the head shortly after the shooting.

RELATED: Former OU punter fatally shot at Oklahoma airport

Southwest Airlines released the following statement:

"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.

"As a result of the police investigation, local flight operations have been halted. We're working to accommodate Customers still in the airport when it was locked down as well as cancelling flights departing from Oklahoma City for the remainder of the day.

"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."
A Southwest Airline employee was shot and killed at the Oklahoma City airport Tuesday, Nov. 15. (KWTV/CBS photos)

Winchester was a former punter for the University of Oklahoma Sooners football team from 1984 to 1986 and played for the university's national championship team, reports USA Today. Southwest Airlines confirmed that he was an airline employee. He is also the father of an NFL football player, James Winchester, who plays for the Kansas City Chiefs.

Michael Winchester, the father of Kansas City Chiefs long snapper James Winchester, was fatally shot in a parking area at Will Rogers World Airport in Oklahoma City on Tuesday afternoon. 

Joe Castiglione, director of athletics for the University of Oklahoma, tweeted, "Our hearts are truly heavy for the entire Winchester Family. Mike was a former Sooner student athlete as was his son James/daughter Carolyn."

Our hearts go out to a great Sooner family. pic.twitter.com/o5sPxKB3B5

— Oklahoma Football (@OU_Football) November 16, 2016