A crazed driver rammed a car into a gate of the FBI’s Pittsburgh office early Wednesday before walking away “like nothing happened” — in what the agency is treating as “an act of terror.”

Donald Henson, a military veteran with a history of mental health problems, was busted after an hours-long manhunt following the 2:40 a.m. attack, the FBI said.

His white Toyota was covered in profane messages when it was plowed into the back gate of the building on the Steel City’s south side — with the driver getting out and hurling an American flag over the fence while shouting incoherently, according to CBS News.

Donald Henson, a military veteran with a history of mental health problems, was busted after an hours-long manhunt following the 2:40 a.m. attack, the FBI said. FBI

“We look at this as an act of terror against the FBI,” said FBI Pittsburgh Assistant Special Agent In Charge Christopher Giordano.

Nakeisha Brown, who works nearby, told WTAE she heard screeching tires and saw the suspect yelling before he left the scene.

“He got out and went around the passenger side and pulled something out of the passenger side,” she said. “I thought it was a gun, but it happened to be a flag, and he just set it on that fence and started yelling out some words and just took off.”

“He just walked away like nothing happened,” said another nearby worker, Idez Columbie.

The driver allegedly tried to blow through the back gate of the FBI Pittsburgh office. KGO-TV

Nobody was hurt in the incident. FBI Pittsburgh

The car appeared to have some profanity-laced messages on one of its side windows, Giordano said, without elaborating on what was written.

Henson was known to FBI agents because he recently went to the office to make a complaint that didn’t “make a whole lot of sense,” Giodano said, according to the Pittsburgh Post-Gazette.

A witness claimed the suspect just walked away “like nothing happened.” KGO-TV

He has a history of mental illness, officials said.

A bomb squad was called, and the white Toyota was searched by authorities outside the gate, footage from the scene shows. Nobody was hurt during the attack.