Gardaí were searching last night for a scrambler bike involved in a crash that left a toddler in hospital with serious injuries.
The 18-month old boy was sitting on a stationary quad bike with his mother when the scrambler smashed into them.
The incident happened in Cherry Orchard Park, Ballyfermot, at around 7pm on Thursday.
Emergency services rushed the child to Crumlin Children's Hospital, where he remains in a serious but stable condition.
The 19-year-old scrambler rider was taken to St James's Hospital with non-life-threatening injuries.
Gardaí are expected to interview him once medics give them the go-ahead.
Investigators are searching for the scrambler, which was removed from the scene before emergency services arrived.
"The bike involved in this incident was removed and gardaí are anxious to track it down as part of their inquiries," a source told the Herald.
"Its removal from the scene can only be seen as an effort to frustrate the investigation into this shocking incident."
The scene at Cherry Orchard Park was preserved for a technical examination.
Gardaí are appealing for witnesses to the incident or people who are aware of the scrambler's whereabouts to come forward.
Local Fianna Fail councillor Daithi de Roiste said off-road vehicles have Dublin communities "under siege".
"This is an awful tragedy that has me sick to my stomach," he said. "My thoughts and prayers are with the child and the family at this time.
"Quad bikes and scramblers have communities under siege right across Dublin, and this is yet another horrible incident in the litany of terrible collisions we've seen in recent times.
TD Patrick Costello, the Green Party's spokesperson on justice, has called for stricter regulation of scramblers and quad bikes.
"We've been going back and forth on this issue for years now," he said.
"How many people need to be injured before we improve regulation around this area?
"It's time to get tough and crack down on the use of scramblers and quad bikes.
"Scramblers and quad bikes were designed for off-road use. They don't have a tax disc or a licence plate, and those who use them don't require a licence.
"These bikes are loud and intimidating and are destroying the quality of life in many estates throughout the country, particularly communities I represent in Dublin South-Central. It has to stop."