Gardai believe the driver of a four-wheel drive vehicle they are looking for in connection with the apparent "road rage" killing of a 21-year-old man in Dublin early on Sunday morning took a flight to the UK later that day.
The 37-year-old suspect was driving the British-registered Vauxhall Frontera which killed Mr David Keating, of Delaford, Templeogue.
Senior Garda sources confirmed last night that he had left the State only hours after the killing. The man gardai are seeking is believed to be an Algerian who has lived in Ireland for several years.
Gardai were maintaining a cautious approach to the case yesterday, despite the fact that they knew the assailant's identity and address. His companion, an Algerian man who was in the vehicle when the incident happened, came forward yesterday.
No identikit pictures of the suspect were released last night while gardai still had hopes that the man might be found or present himself. A full description is likely to be issued later today.
The grey four-wheel drive vehicle involved in the incident was found abandoned in Crumlin on Sunday night.
The incident took place at the junction of the South Circular Road and Emor Street. The four friends were on a pedestrian crossing on Emor Street on which they had right of way over traffic.
It is understood the Frontera drove through the crossing, narrowly missing three of the youths. It is believed they shouted at the Frontera and the driver stopped and an argument began. One of Mr Keating's friends was struck on the head with a baseball bat.
Mr Keating, who was trying to call a taxi from his mobile telephone, was across the street and crossed to help his friends. He also called the Garda on his telephone. It is understood the driver then got into the car and began trying to drive away. Mr Keating stood in front of the car and may, at one stage, have been holding on to the bonnet.
It is believed the vehicle swerved to throw him off and he may have fallen under a rear wheel. He suffered head injuries and was declared dead on arrival at St James's Hospital.