Three men arrested over the murder of a kickboxer who was beaten to death have been released without charge.
Niall Dorr, 18, died in hospital on Thursday night after suffering serious head injuries in a row involving several youths.
Senior investigators are trying to establish a motive for the attack on Wednesday night on Castle Road, Dundalk.
Three men questioned, aged 21, 23 and 30, were earlier released from custody.
A garda spokesman said a file is being prepared for the Director of Public Prosecutions. Gardai have appealed for 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."