The victim, who has been named locally as Dermot Byrne, was naked when he was found by a passer-by on a Dublin street in the early hours of yesterday morning.
The grim discovery was made on a set of steps at Fingal Community College, on North Street, in the north Dublin town of Swords at 3.05am.
Sources say that Mr Byrne, who lived in Swords, suffered multiple blunt force injuries to his head and body, which were consistent with a prolonged and sustained beating.
It was likely that the attack had happened elsewhere and that Mr Byrne was later dumped on the street. His injuries were so bad it is suspected that whoever carried out the attack may have believed he was dead when they dumped him.
A Dublin Fire Brigade tender and HSE ambulance from Swords were dispatched to the scene, and teams of paramedics battled to save Mr Byrne's life.
The victim had a faint pulse when the emergency crews arrived, but died in the ambulance while being treated.
A 29-year-old man was arrested yesterday evening in the Dublin area in connection with the garda investigation. He was being detained at Swords garda station last night.
A post-mortem examination was carried out on Mr Byrne's remains yesterday to determine the exact cause of death.
"Swords is a lovely place to live, but it's awful how something like this can happen to someone on the streets of this town."