A teenager who was caught on CCTV stamping on an unidentified man’s head and using a bicycle as a weapon during a group attack has been jailed.Dublin Circuit Criminal Court heard the victim left the scene after the assault, and despite extensive efforts including checks with hospitals, gardaí have been unable to identify him.Adam Farrell, aka Tierney, (18) of Shangan Garden, Ballymun, pleaded guilty to assaulting an unknown person with intent to cause bodily harm at Centra, Coultry Park, Ballymun on February 5th, 2026.An investigating garda told prosecuting barrister Mark Murphy that gardaí responded to a report of a group of youths fighting outside Centra but found no one there when they arrived. They viewed CCTV from the area and identified Farrell and a second man.The footage showed Farrell and another man confronting a male, who was knocked to the ground, where Farrell stamped on his head and used a bicycle as a weapon to hit the man on the ground.Farrell was identified, arrested and interviewed. He has 30 previous convictions.Defending barrister Oisin Clarke outlined his client’s history, highlighting that he was a vulnerable young man who was easily led and had been diagnosed with dyslexia and dyscalculia.He said he had a difficult time in education but was a keen footballer until he suffered a leg injury in a car accident. He said Farrell also suffered the tragic loss of an older brother when he was 13-years-old.He handed in a number of references, including from an uncle who is a professional footballer. Another letter described how Farrell continued to help with jobs around the grounds of his former club after he stopped playing. He had support from his family in court.Clarke outlined how Farrell had fallen in with a bad crowd and began using cannabis.Counsel observed it was a nasty offence and said a woman who can be seen remonstrating with the victim before the assault was accusing the victim of theft. He said Farrell should not have involved himself but submitted that he was a person without long-term thought processes who acted spontaneously. He accepted he did not have medical reports to this effect before the court.Clarke said Farrell was doing well in the structured environment of custody and dealing with his issues. He submitted that Farrell could be a positive member of society if he put his mind to it and had plenty of time to put his life back on track.Passing sentence on Friday Judge Orla Crowe said the viciousness of the beating had been evident on viewing the CCTV footage. She said while Farrell was not the protagonist, he had an active role in subjecting the injured party to a vicious attack.The judge noted Farrell was apologetic and had entered an early guilty plea. She noted his unusual personal circumstances and the references before the court.She said it was a serious assault, notwithstanding that the injured party had not been identified or made a complaint, and had to be marked with a custodial sentenceCrowe sentenced Farrell to 2½ years’ imprisonment with the final 12 months suspended.