One of the seven Dubliners on trial charged with murdering 20-year-old Dale Creighton has pleaded guilty to violent disorder on the footbridge where the deceased was assaulted.
A witness also told the jury that he saw a knife in Mr Creighton's hand that morning.
Dale Creighton died on January 2 2014, about two days after an incident at the footbridge over the Tallaght bypass between Saint Dominic's Road and Greenhills Road.
Jason Beresford (23) with an address at Coill Diarmuida, Ard A Laoi, Castledermot, Co Kildare, went on trial with six others on Tuesday.
The woman and six men, who are in their 20s and from Tallaght, all pleaded not guilty to murder when arraigned before the Central Criminal Court last week. Each accused also pleaded not guilty to violent disorder at the footbridge that New Year's Day.
However, when the jury arrived to court yesterday morning, Mr Beresford's barrister, Micheal O'Higgins SC, asked that his client be re-arraigned on the second count against him.
Dressed in a grey suit and shirt and a navy tie, Mr Beresford stood up and pleaded guilty to violent disorder on January 1, 2014.
Ms Justice Deirdre Murphy told the jury that one of the counts had been disposed of and that the trial would proceed as normal.
Also charged with both offences are 23-year-old Aisling Burke and 28-year-old David Burke, both with a current address at Beechpark, Collinstown, Co Westmeath; Graham Palmer (26) with a current address at Park Avenue, Portarlington, Co Laois; Ross Callery (23) currently of Gortlum Cottages, Brittas, Co Dublin; James Reid (26) currently of Glen Aoibhinn, Gorey, Co Wexford; and Gerard Stevens (27) currently of Grosvenor Square, Rathmines, in Dublin.
The jury also heard from a witness, who said he saw Mr Creighton with a knife on the footbridge in the early hours of that morning.
Carl O'Leary said that he was on his way to get a taxi in Tallaght village some time after 3am, when he heard a commotion.
"I vaguely remember someone running past me," he recalled.
"I just remember someone saying: 'Grab him. He robbed our phone'," he testified. "I recall seeing James Reid and Ross Callery."
He said there were others, but he didn't know who they were.
Mr O'Leary said he, himself, began running down the Tallaght bypass and towards the footbridge.
"I remember seeing Mr Creighton on the bridge. I didn't know him at the time," he said.
Under cross examination by Brendan Grehan SC, defending Ms Burke, he agreed that he had put two and two together when he saw the person running and heard the shout about the phone.
"I ran down after him. I just assumed he'd robbed the phone," he explained. "I thought I was doing the right thing."
Mr Grehan then read from his statement to gardai.
"I seen he had a big kitchen knife, probably in his right hand. I said to myself: 'F**k, I'm not risking getting stabbed for nobody's phone'," he had said. "I stopped."
He said in court that he hadn't seen the knife when he backed away from Mr Creighton, but had done so because Mr Creighton had run at him.
He confirmed to Ciaran O'Loughlin SC, defending James Reid, that he had later seen Dale Creighton with a knife, but said he hadn't seen Mr Reid take the knife from him.
Mr O'Leary's girlfriend, Shannon Downes, also testified yesterday. She said that she had initially seen two males running by her while in the village that morning.
"A girl came running after them around the corner, saying they'd robbed her phone," she recalled, explaining that Mr O'Leary had run off to get her phone.
She was cross examined by Mr Grehan, who read from the statement she had made to gardai about what she'd heard: "He's after bashing me and robbing my phone."
She agreed that this account was correct. The trial continues before six men and six women.