Gardai are trying to trace the drivers of two cars that overtook a bus minutes before it crashed, killing a teenage girl.
The accident happened on the Greenhills Road in Walkinstown at about 5pm on Sunday.
Gardai said they would like to speak to the drivers of two cars, possibly silver, which were in the area of the crash between the Walkinstown roundabout and Ballymount junction at the time.
The cars overtook the number 27 bus while it was at a bus stop on the Greenhills Road shortly before the collision.
A 19-year-old man who was driving the car suffered serious injuries and is being treated in Tallaght hospital.
The bus driver and one passenger were taken to St James's Hospital with minor injuries.
Gardai in Crumlin have appealed for witnesses.