Gardai are investigating if a car involved in a fatal head-on collision in Dundalk on Tuesday night was racing another car before the crash.
Barry Griffin (17), who was a passenger in one of the cars, was killed when the incident occurred at Ballymascanlon at around 9pm.
The driver of that car, a 07 registered Volkswagen Passat, left the scene on foot after the crash, but later presented himself to a garda station where he was being questioned last night.
The driver of the second car, a man in his 40s driving a Ford Kuga, was taken to Our Lady of Lourdes Hospital in Drogheda with minor injuries.
He was not involved in any racing and was innocently driving in the opposite direction towards the cars believed to have been racing each other, and collided with the Passat head on.
Gardaí believe that a car which was said to be racing the Passat at the time of the crash was then driven over the Border and burned out.
A youth is also being questioned in relation to that vehicle, thought to be a Mercedes.
"It looks like the Passat was being raced against the second car, which was bought cheaply up North, when this incident occurred," said a source.
"The crash was on a fairly straight stretch of road close to Ballymascanlon roundabout.
"There were four people in one car and the passenger was killed and the driver fled, while the other passengers remained at the scene.
"There was one occupant of the Ford and he received minor injuries," they added.
The road remained closed for a technical examination yesterday while local diversions were in place.
Tributes were being paid to Barry Griffin yesterday as his family and the community of Castle Heights where he lived were coming to grips with the tragic news.
Local sources say Barry would have sat his Leaving Cert at De LaSalle College in Dundalk this year but for the Covid-19 pandemic.
He also played in the past with the Shamrocks football club in the schoolboy league.
One friend posted a message on Facebook saying her heart goes out to his family.
"My heart is absolutely broke writing this. For all who knew Barry he was one of the most genuine people about. He never meant any harm, always had a smile on his face, always made others smile and was one of the funniest people I know," she added.
"We're all in shock of what happened but we all loved Barry. We love and miss you, we hope you get the best bed in heaven and to always look down on us."