On the night of April 25, 2016, father-of-five Mr Barr was socialising at the pub, where he was a manager, and was shot seven times - five times in the head - after two armed males burst in wearing what have been described as 'Freddy Krueger' masks.
At the non-jury court yesterday, Christopher Slator spoke only to plead not guilty to the accusation of murdering Mr Barr.
Mr Slator (37), of Carnlough Road, Cabra, Dublin 7, is accused of the murder of Mr Barr at the Sunset House pub on Summerhill Parade in Dublin 1 on April 25, 2016.
Opening the prosecution case, Dominic McGinn SC said it will be the State's case that two armed men in boiler suits and masks entered the bar at around 8.30pm on the night and shot Mr Barr.
Mr McGinn said that these two men then ran from the bar to a waiting silver Audi vehicle, which was later observed on fire in the Walsh Road area of Drumcondra.
Counsel said that it will be the State's case that three men were then seen running from the burning Audi toward a silver Mondeo.
Mr McGinn said that a Garda investigation will show that CCTV made it possible to track the movements of the Audi from a lock-up in the North Circular Road area before the shooting to the Sunset House and then to Walsh Road.
He said that on the night of the murder, gardaí arrived at the scene of the burning Audi and were able to recover four firearms, two of which will be shown to have been used in the shooting.
Mr McGinn said the State will show that boiler suits, full "theatrical head masks" and a balaclava were also recovered from the Audi.
Counsel said it will be the State's case that a discarded mobile phone, found at the scene of the burning Audi, can be traced to a mobile phone shop in the Ilac Centre. Counsel said CCTV revealed the buyer to be Martin Aylmer of Casino Park, Marino, Dublin 3, who was jailed in 2018 for his participation in the murder.
Mr McGinn said that while no "meaningful" prints could be taken from the Audi, it is the State's case that three DNA profiles taken from masks and balaclavas in the car revealed Mr Slator's profile to be present on a mask and a pair of gloves.
Another DNA profile from the masks and a baseball cap, said counsel, belonged to Eamon Cumberton, of Mountjoy Street, Dublin 7, who was jailed for life for the murder in 2019.
In November 2020, David Hunter (43), of Du Cane Road, White City, London, was jailed for life for the murder of Mr Barr.
Presiding judge Ms Justice Tara Burns adjourned the case to today.