OKLAHOMA CITY - The Will Rogers World Airport are slowly resuming operations after a shooting suspect was found dead.

The airport was put on lockdown after reports of a shooting shortly before 1 p.m. Tuesday, said police.

Oklahoma City police confirmed Michael Winchester, 52, who worked for Southwest Airlines was gunned down at work.

"When you have a potential suspect inside a building as big as the airport and several levels of parking garage to search, it's going to be time consuming," said Oklahoma City police Capt. Paco Balderrama.

After a five-hour lockdown, police announced the suspect had been located in a red pickup on the second level of the parking garage.

"When there is a vehicle that is potentially booby trapped ... we have to take our time to clear the vehicle," said Balderrama.

Police said a the tactical unit used a technique to blowout one of the windows but it was difficult to distinguish if the suspect was still a threat.

A tactical robot was used to get a closer look.

Police confirmed the suspect was dead from an apparent self-inflicted gunshot wound.

The identity of the suspect has not been released.

"We believe it was premeditated -- not random," said Balderrama.

Police explained the suspect obviously knew Winchester's work schedule and waited for the victim to arrive or leave the airport.

UPDATE: Law enforcement sources have identified the shooter as Lloyd Buie.