WASHINGTON — For the first time in decades, the F.B.I. is trying to fire an agent for intentionally shooting a suspect, after finding that the agent violated bureau policy when he wounded an unarmed man who had apparently helped break into his Lexus outside his home in Queens.

The agent, who was off duty, fired at the man from a second-story window, hitting him in the back. The man claimed that he was running away when the agent shot him, but a government investigation concluded otherwise. Still, the bureau deemed the decision to fire a “bad shoot,” in agents’ parlance.

The F.B.I. has not announced its finding about the shooting, which took place on July 18, 2012. But the bureau provided three internal reports about the investigation to The New York Times in response to Freedom of Information Act requests.

It is extraordinarily rare for the F.B.I. to deem improper an intentional shooting by one of its agents. The bureau faulted the agent for violating its lethal force policy about six months after The Times reported that the F.B.I. had found to be justified at least 150 consecutive shooting episodes dating at least to 1993.