TULSA, Oklahoma - A security officer shot and killed a man outside a Tulsa hospital. Guards said it started when the man tried to break into cars in the Hillcrest parking lot.

Police said the man had a gun and Hillcrest security guards chased him. Security tells police, once the man showed the gun, a guard opened fire.

Police said they found evidence that the man was trying to steal a motorcycle and pulled his gun on security.

A shooting scene on the Hillcrest Medical Center Campus shut down busy streets near the hospital Friday afternoon.

Witnesses visiting their father saw security guards chase a man.

"We were in the parking lot. He ran literally in front of us," Verna O'Malley said.

Security guards told police they got a call about a man trying to break into cars in the lot on the west side of the campus.

The guards told police they confronted the man, the man tried to get away and security even tried using pepper spray to take him down.

"The male resisted, the security officer saw the male with a gun, the security officer fired upon that individual and killed him," Sergeant Dave Walker, with the Tulsa Police said.

Tulsa Police say EMSA pronounced the man dead at the scene.

Sitting on his porch across the street, James Reinert saw the man running from the guards.

Reinert said, "I heard him holler, 'put the gun down, put the gun down.'"

Reinert didn't know what happened until he heard a loud noise.

"When he jumped, all I heard was a pop," he said.

Police said the Hispanic man shot and killed by the guards is between 30 and 40 years old.

O'Malley said she doesn't know why security guards had to shoot the man.

"He was gaining momentum and there were several security cops on foot chasing him and two in vehicles and they said, 'stop' and another one was walking, and we heard the gun shot as soon as they said stop," she said.

Witness, Tia Claybrook, said, "It scared me, it scared the crap out of me."

The security guard has been released.

Investigators say they found a loaded gun next to the man who died.