A man who was fatally shot Tuesday night during a Gwinnett police investigation at a home in unincorporated Lawrenceville committed suicide, the Gwinnett County medical examiner has ruled.

Two detectives were interviewing witnesses in a terrorist threats case when Hien Trong Luong, 62, pulled up to the house in a minivan, police said. Luong knocked on the door and the detective who answered recognized him and identified himself as police.

He ordered Luong to take his hands from his pockets. Luong refused, police said, then pulled a handgun from his pocket and pointed it at his own head. He refused to drop the gun and, after a few seconds, fired one shot into his head.

One of the detectives fired a shot immediately after. It missed Luong who died at the scene.