A YOUNG man leapt on a garda's back, pulled his stab vest and punched his head while a violent inner city disturbance raged, a court heard.
Lee Coakley (23) claimed he was trying to help his aunt up off the ground and had nothing to do with the assault on the garda amid scenes of "chaos".
But he was identified by gardai as being the assailant because of the distinctive "mohican" haircut he had at the time.
Judge Catherine Murphy found him guilty of assault but said she would leave him without a conviction if he made a charity donation.
Coakley, of Liberty House, James Joyce Street, Dublin, had pleaded not guilty to a charge of common assault on Garda Declan Crushell in the incident at the junction of Sean McDermott Street and Gardiner Street on August 22, 2009.
Judge Murphy dismissed a charge of violent disorder, but Coakley admitted a further charge of obstructing gardai as they arrested him.
Garda Crushell told the court he was at the scene of the disturbance involving a large group of people at 6.35pm when he saw another man strike an officer several times in the face and body.
As he attempted to restrain this suspect, he felt a force on his stab vest as if somebody had grabbed it and was trying to pull him away.
He also felt a heavy blow to the back of his head which startled him momentarily.
He then drew his baton and felt a blow across his lower back as he turned.
He saw a woman in her early 40s, wearing a pink tracksuit, waving a walking stick in the air.
"It was quite chaotic, I wasn't sure where the next blow was going to come from," he said.
The accused was among the crowd, but the garda was not able to say if he had assaulted him.
However, another garda gave evidence that it was Coakley.
The defendant said he was not involved in the disturbance but was in the area when he saw his aunt lying on the ground.
He was trying to get her up and keep her safe from the "chaos" around them, he said.
Coakley apologised for his reaction to being arrested.
The court heard he had no previous convictions, had worked as a tiler and set up a local football club.
His partner was expecting their first child.
Judge Murphy said it had been a "disgraceful" incident but she did not want the accused's life to be "blighted" by a conviction.
She adjourned the case to October 7 and said she would strike the charges out if the defendant made a €500 donation to Temple Street Children's Hospital.