A woman accused of manslaughter said "alcohol consumption" caused a row on the night a student was fatally injured, a court was told.
Andrew Dolan (20) died on January 1, 2012, from injuries sustained during an assault.
Jessica Hughes (21), of Rathwire, Killucan, Co Westmeath; and Patrick Daly (23), of Mulphedder, Clonard, Co Meath, both deny unlawfully killing Mr Dolan from Carrick-on-Shannon, Co Letrim.
Mr Daly further denies a charge of assaulting Ian Farrell on the same night.
It is alleged that Ms Hughes, Mr Daly and a Patrick Farrell delivered a total of six blows to Mr Dolan during an altercation at Pearse Street, Mullingar, on December 23, 2011 at around 2.40am.
Farrell, who delivered the last blow before Mr Dolan fell and hit his head on the ground, has admitted manslaughter.
Mr Daly was arrested for public order offences shortly after the incident on December 23. He was taken to Mullingar garda station where Farrell was also being held.
Shortly after 4am, Garda Sergeant Roger Nicholson spoke to Ms Hughes who was waiting at the reception of Mullingar garda station.
"She said she was waiting for her boyfriend who was arrested," he explained.
He said Ms Hughes, who had been drinking, told him her hand was sore from hitting someone.
At this point Sgt Nicholson cautioned Ms Hughes.
"She stated again that she hit a man twice with her hand," he told the court.
When asked what started the row, she gave what Sgt Nicholson described as an "abrupt answer -- alcohol consumption".
Mr Daly was arrested on suspicion of assault and interviewed on December 24.
He said: "It all started out of a verbal argument, that's how it all kicked off."
He also said a comment was made prior to the altercation and he admitted: "I came in and hit him a slap, I must have."
The trial continues.