Atlanta police are investigating after a man was shot and killed by a security guard early Saturday at a 24-hour diner.

The shooting happened about 4 a.m. at the Midtown Diner on Peachtree Street, Atlanta police spokesman Officer Anthony Grant said. Officers arrived at the restaurant and found a man with at least one gunshot wound. He was taken to the hospital, where he died of his injuries.

The fatal shooting stemmed from a fight between the man and the diner’s security guard, but few details have been released. The security guard remained at the scene and is cooperating with detectives, authorities said. He has not been charged.

“Investigators still aren’t sure how this started between the guy and the security guard,” Grant told The Atlanta Journal-Constitution. “The shooter is cooperating.”

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