(NewsNation) — A driver rammed a car into a security gate at the FBI building in Pittsburgh before throwing an American flag over the gate and fleeing, authorities said.

According to the FBI, the incident occurred overnight Wednesday at around 2:40 a.m. local time. Public affairs officer Bradford Arick told NewsNation the agency has identified the driver as Donald Henson.

Arick said Henson had previously visited the Pittsburgh FBI field office to file a complaint, but the investigation was not escalated. Arick said there appeared to be "some mental health concerns."

Investigators said they found writing on the side of the car Henson was driving but did not elaborate on what the message said.

Henson was still on the run Wednesday morning, and he is believed to be unarmed. Authorities ha

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