A Dorchester man was ordered held without bail Thursday at his arraignment on charges he shot a man to death after a Christmas-eve concert.

Ian Holness, 27, stood behind a door as murder and illegal-weapons charges were read against him in Dorchester District Court this morning, frustrating the relatives and friends of Rashaan O'Neil, 36, who wanted to get a look at O'Neil's accused killer.

Assistant Suffolk County District Attorney Lynn Feigenbaum said both men attended a concert at Russell Auditorium on Talbot Avenue, in separate groups on Christmas eve, then, after it got out, retired to 92 Wales Ave. - right behind the auditorium - for an after party.

Around 4 a.m., Christmas day, Feigenbaum said, O'Neil was standing in the basement talking to some people when Holness came up behind him with a gun and shot him once in the back of the head.

Virtually the entire party, including Holness, rushed up the stairs and out the doors - although not before one party-goer tried to stop Holness, who waved a gun at him, the prosecutor said.

Meanwhile, O'Neil lay on the basement floor on his side, dying, Feigenbaum said. By the time EMTs arrived, he was "non viable" and declared dead at the scene, she said.

After fleeing the party, Holness got into his silver 2002 Jaguar and sped off - but only after shooting at another car occupied by women who had also been at the hospital - sending one of its occupants to Carney Hospital with non-life-threatening injuries - and then crashing, Feigenbaum said.

She said Holness then ran away - but showed up at B-3 later that day to inquire as to where his car had gone. He quickly retreated when told his car had been towed away for safe keeping, she said.

Detectives arrested Holness Wednesday.

Feigenbaum said shells recovered from Wales Street, the crash scene and from inside the Jaguar were all fired from the same gun.