A former Illinois deputy police chief from the Chicago suburb of Midlothian was convicted of using excessive force for his role in a 2011 Thanksgiving Day incident in which he beat a man leaving a bar with his police baton for no reason.

James Snyder had just left a Midlothian bar early Thanksgiving morning three years ago when he heard someone shout at him from across the parking lot and was suddenly charged by several men.

Testifying in federal court, Snyder said that as he tried to run back to the bar for help, he felt blows from a metal object raining down on his head and back. He sought refuge behind a uniformed police officer who’d been called to the scene and heard what he thought were commands for the assailant to get on the ground.

But it turned out Snyder’s attacker wasn’t under arrest, he was the one in charge.

Jurors deliberated for just two hours at the end of the three-day trial, Friday, before deciding that Zamiar acted unreasonably when he repeatedly beat 31-year-old James Snyder in the back and head with a steel baton in the early hours of Thanksgiving 2011.

They may have been swayed by the testimony of Sgt. Edmond Olmos, who took the highly unusual step of testifying against a superior officer when he gave eye-witness testimony backing Snyder’s claim that Zamiar’s attack in the parking lot of Durbin’s bar was unprovoked.

Federal prosecutors said Zamiar used potentially deadly force when he beat Snyder with a steel-reinforced baton after responding to what appeared to be a drunken disturbance at the bar.

Zamiar had claimed that Snyder had squared up to him in a “fighting stance” and was throwing a punch when Zamiar hit him in self-defense.

Zamiar was fired last year, following his indictment.

Friday’s verdict leaves unresolved a second federal criminal charge against Zamiar, who is also accused of an unprovoked 2010 attack on a detainee. That case was due to go to trial in January, but has now been postponed.

Though federal law calls for defendants convicted of crimes of violence to be immediately taken into custody in all but extraordinary circumstances, Zamiar has been allowed until April to challenge his detention. He faces up to 10 years in prison when sentenced.

Zamiar, who has also been sued five other times in federal court for police brutality, also faces a civil lawsuit brought by Snyder.