Three men remain in garda custody today over the murder of a kickboxer who was beaten to death.
Niall Dorr, 18, died in hospital on Thursday night after suffering serious head injuries in a row involving several youths.
Three men, aged 21, 23 and 30, are being questioned at Dundalk and Drogheda Garda Stations under Section 4 of the Criminal Justice Act.
Senior investigators are trying to piece together a motive for the attack on Wednesday night on Castle Road, Dundalk.
Gardai urged anyone in the area between 9pm and 9.30pm to come forward, particularly a motorist who reported the incident to a patrol car and parishioners attending a novena in nearby St Joseph's Redemptorist Church.
Mr Dorr, of Avondale Park, is survived by his parents David and Veronica and older brother Shane.
The former St Mary's College student had been for an interview with the army just hours before the row.
Con McGinley, principal, described him as a pleasant and courteous teenager.
"When you see a decent family like that get ripped apart by a tragedy like this your heart just goes out to them," he said.
Mr Dorr, was also a member of the Cobra-Kan kickboxing club in Dundalk.
Patricia McQuillan, coach and founder of the club, said: "He was the most polite and best mannered of young people you could meet."