A bruising battle at the Avenue Tavern in Mattapan Square that sent three to the hospital on March 6 was due to some "older kids" trying to re-assert their authority in the neighborhood after 8 1/2 years in prison, a bar manager told the Boston Licensing Board today.

The board decides Thursday whether to levy any penalties against the bar for the fight and for a follow-up inspection a week later that found far more people inside than allowed by the bar's license.

Bar manager Karen Brown said the fight, which started around 1:20 a.m. at the 1583 Blue Hill Ave. bar, was between a group of young regulars and a pair of malcontents fresh out of prison and their pals.

Brown said the "young kids" had been coming every Friday for about a year with no problems, in contrast to the "older kids" - now in their 40s - several of whom she had barred from entrance because they refused to be patted down or even show ID.

"They just came back thinking they run the town," she said. One warned her, "I run [things] here," but she said she replied, "I don't care. As long as you're in my door, I run [things] and that was that."

Det. Sgt. John Fitzgerald of District B-3 said the incident is still under investigation.

He told the board that as EMTs were getting one injured man ready for transport to the hospital, police asked him if he had any weapons on him. Fitzgerald said the man surrendered a knife with with appeared to be blood on its blade.

Not long after, he said, police got a call from Carney Hospital about a man with a stab wound to the stomach. As officers were interviewing him, a third man walked in, with cuts on his head from what he said was a glass beer bottle at the bar.

Fitzgerald said that when detectives returned to the bar around 2:40 a.m., it was all locked up - with the interior still strewn with cups and trash. What appeared to be blood remained splattered outside the front door and in the rear of the building, he said.