OKLAHOMA CITY (AP) A man who gunned down a Southwest Airlines employee outside of Oklahoma City's airport likely did so in retaliation for having lost his own job with the airline last year, police said Wednesday.

Lloyd Dean Buie, 45, killed 52-year-old Michael Winchester on Tuesday as Winchester was leaving work and walking to an employee parking lot, police Capt. Paco Balderrama said at a news conference. Buie fired the shot from the fourth floor of a parking garage when Winchester was about 50 yards away, he said. Buie was later found dead in his pickup truck in the garage. Police think he shot himself.

''We know his intention was to go to the airport to hurt someone,'' Balderrama said. ''The suspect knew where the employees parked and where they would be walking.''

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Buie quit his job as a ramp agent for Southwest Airlines in April 2015 after he refused to take an alcohol screening, airline spokeswoman Brandy King said Wednesday. She said co-workers had suspected Buie was under the influence at work, but she declined to say if Winchester, a ramp supervisor who had worked for Southwest for 29 years, was involved or to describe any interactions the two men may have had.

''Our Southwest family is grieving, as we are deeply saddened by the loss of our family member. Our focus remains on offering support to the Winchester family and Southwest employees during this difficult time,'' King said.

Police said Winchester wasn't Buie's immediate supervisor, but they believe the incident that led to Buie's resignation likely served as motive for the attack.

Winchester, who has a listed address in Washington, a community about 35 miles south of the airport, was a former University of Oklahoma football player whose son James is a long snapper for the Kansas City Chiefs.

Chiefs players and coaches expressed support for their teammate Wednesday, with head coach Andy Reid saying James Winchester had returned to Oklahoma to be with his family and that he didn't know if he'd return in time for Sunday's game against Tampa Bay. Punter Dustin Colquitt said he spoke to Winchester, who told him: ''Obviously this is a tough time for my family, but I appreciate the thoughts and prayers.''

The shooting set off a scramble at Will Rogers World Airport, with police immediately closing the sprawling complex and asking passengers to seek cover. They diverted incoming flights and refused to give already-loaded aircraft permission to leave. There were concerns the gunman might have entered the terminal and mingled among passengers or employees.

Police found Buie's pickup truck in the parking garage about three hours after the shooting. They used a robot to determine he was dead inside it before giving the all-clear.

Balderrama said Buie likely would have needed a scope on his rifle to shoot Winchester from that distance.

''It would definitely require familiarity with a rifle,'' he said. ''You don't have to be an expert marksman to hit a 50-yard shot, but it's not an easy shot either.''

The attack led to the cancellation of 25 flights. Normal airport operations resumed Wednesday.

The airport handles between 7,000 and 8,000 passengers daily for Alaska, Delta, Southwest and United airlines and has a separate terminal that serves as a transfer center for federal inmates. A jet carrying inmates to the transfer site was allowed to land while the rest of the airport was shuttered.

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Associated Press sports writers Jim Vertuno in Austin, Texas, and Dave Skretta in Kansas City, Mo., contributed to this report.