One of seven people accused of killing a Dubliner identified himself holding a knife in CCTV footage of the fatal assault during garda interviews, but denied stabbing the 20-year-old.
The trial heard that the deceased, Dale Creighton who was beaten to death on New Year's morning 2014, also had a stab wound to his leg.
The court heard that James Reid described what he was shown as 'horrific'.
The incident took place around 4am at the footbridge over the Tallaght bypass between Saint Dominic's Road and Greenhills Road. Dale Creighton died in hospital on January 2nd 2014.
A woman and six men, who are in their 20s and from Tallaght, have all pleaded not guilty to murder and went on trial at the Central Criminal Court on Tuesday.
They 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; Jason Beresford (23), with an address at Coill Diarmuida, Ard a' Laoi, Castledermot, Co Kildare; and Gerard Stevens (27), currently of Grosvenor Square, Rathmines in Dublin.
Each accused also initially pleaded not guilty to violent disorder at the footbridge that New Year's Day. However, Jason Beresford changed his plea on Wednesday and pleaded guilty to the violent disorder charge.
Garda Brian O'Connor testified that he arrested James Reid at an address in Tallaght on the morning of January 2. He and colleagues then interviewed him at Tallaght Garda Station.
Mr Reid said he did not know Dale Creighton, but had heard something about a girl's phone being stolen that morning.
It was put to him that Mr Creighton was dead as a result of his and his friends' actions.
"It wasn't me," he replied.
He was asked which part he had taken in the assault.
"I had no part in it," he said.
It was put to him that, as far as the garda could make out from the CCTV, Mr Creighton was kicked, punched, stabbed and thrown down a set of concrete stairs.
He was then shown footage of the incident on the bridge and asked if he had anything to say.
"It's horrific," he responded.
He agreed that he was on the video and identified himself, but repeated that he hadn't assaulted the deceased.
The footage had already been played to the jury, but was replayed so Gda O'Connor could point out the figure Mr Reid had identified as himself.
"What are you holding in your hand?" he was asked in interview.
"The knife that I took off him when he swung it at me," he replied. "I jumped back and took it off him."
He agreed that he then walked out of shot with the knife and said he went home.
"I didn't want nothing to do with it," he said.
Under cross examination by Ciaran O'Loughlin SC, defending Mr Reid, Garda O'Connor agreed that he had not seen his client punch, kick, stab or drag the deceased in the footage. He also agreed that he could see him pushing someone away from Mr Creighton.
The trial continues.