A garda grabbed a woman by the throat and locked her in a bathroom while his colleagues beat her teenage son as he slept in bed, a court heard today.
Officers Alan Conlon, Claire Delaney, Eoin Murtagh and Sean O'Leary attacked Owen Gaffney with a baton before he was punched and kicked, it was claimed.
All four are charged with assault causing harm, forcible entry and trespass at the family home in inner city Dublin on February 17th, 2008.
Three of the accused, Conlon, Delaney and Murtagh, are also accused of the false imprisonment of Mr Gaffney's mother Fidelma in a bathroom during the ordeal.
The gardaí, who are suspended from the force, deny the charges.
Opening the trial for the prosecution Tom O'Connell, SC, told Dublin Circuit Criminal Court the incident appeared to be a pre-arranged plan to give the then 17-year-old a beating.
"This case is about guards behaving unlawfully for reasons which will become apparent in the course of the trial," he told the jury of six men and six women.
Mr O'Connell said there had been a history of conflict between a number of gardaí and Mr Gaffney, who lived at the Basin Street flats near St James's Hospital.
The officers, who were travelling in two separate squad cars, are said to have met earlier on the Sunday afternoon where they allegedly made a concerted plan to assault Mr Gaffney. About nine are believed to have been in the vicinity of his home during the incident.
The State barrister said witnesses, including other gardai on duty, will describe how Delaney waved a piece of paper in Mrs Gaffney's face pretending it was a warrant as the others went upstairs unlawfully.
Mrs Gaffney (41) told investigators she followed them to her son's bedroom where she saw Garda O'Leary lift the duvet and hit Mr Gaffney over the head with a baton as another garda kicked him.
She claimed an officer pulled her arms behind her back, grabbed her by the throat and forced her into the bathroom.
Several gardaí then took turns to hold the door handle up to keep her inside for about five minutes, the court heard.
"Another person in the house at the time could hear Mrs Gaffney screaming upstairs and saw guards holding the bathroom door," Mr O'Connell said.
A family friend who had rung Mrs Gaffney just before she opened her front door to officers recorded the incident on his mobile phone, he added.
Three of the gardaí, Garda Delaney (25), Garda Murtagh (30) and Garda O'Leary (34) were stationed in Kilmainham at the time and Garda Conlon (29) was stationed at Kevin Street.
It is claimed that once back in their garda cars Garda O'Leary asked for an antiseptic wipe to clean blood from his baton while Murphy wiped blood off his knuckles.
The victim was taken to hospital and treated for a cut lip, a 2-centimetre bruise on the top of his head, a swollen nose which had been bleeding, a laceration to his right upper arm, and bruising on his upper body, including one on his chest measuring 5cm by 5cm.
Mrs Gaffney lodged a complaint with Detective Sergeant Colette Wheeler, a duty officer in Kilmainham, who revealed there were no planned searches in the Basin Street area that afternoon.
The case was passed to the Garda Ombudsman and a major investigation launched.
Mr O'Connell claimed forensic tests will reveal a one in a million chance that a mix of blood found on the handle of a baton did not belong to Mr Gaffney and Murtagh.
He warned the jury that, while the accused were innocent until proven guilty, members of An Garda Síochána were not beyond the law.
"If they behave unlawfully and if they behave in a manner which is not justified, then of course they are subject to the law like any other citizen," he added.
The trial before Judge Desmond Hogan is expected to last two weeks.