The GBI was called in to investigate whether a DeKalb police officer acted properly when he fatally shot an unarmed man, who appeared to be mentally ill Monday, said Cedric Alexander, director of the county public safety department.

The DeKalb officer responded to an apartment complex around 1 p.m. on a “suspicious person” report in which a man , who lived in The Heights at Chamblee, was knocking on apartment doors, had disrobed and was crawling around naked, Alexander said.

“No weapon was found,” Alexander said. “The GBI is going to take the point on this investigation.”

The man who appeared mentally ill ran at the officer and ignored demands to stop before the officer shot him twice, Alexander said. He said he did not know whether the man was charging or just running, the distance between the officer and the man when the shots were fired or whether the officer should have employed his Taser.

That would all be part of the investigation, Alexander said. The name of the officer, a 7-year-veteran of the force, and the dead man were being temporarily withheld, Alexander said. The officer is on administrative leave.

He said the decision to call in the Georgia Bureau of Investigation was in step with a national move toward having independent agencies investigate officer-involved shootings. Alexander said it was not tied to recent unrest involving a DeKalb police investigation into an officer's fatal shooting of a 44-year-old man who had called 911 for police help.

In that case, Alexander agreed to call in the GBI following demands by the man’s family members and protesters.

DeKalb officers receive some training in dealing with the mentally ill while in the academy before they join the force, Alexander said, but on Monday he said perhaps the training needed to be bolstered.

“That is becoming more and more apparent,” he said.

Staff writers Alexis Stevens and Ben Gray contributed to this report.