The Brazilian community is calling for a speedy inquiry after a man lost part of his leg following an incident with a Garda car.
It came as a group of men working as couriers here were trying to track down a motorbike that was stolen from one of them.
They were following a tracker that was attached to the bike and ended up on the M50 near Tallaght on Saturday afternoon.
23-year-old João Ferreira was among those who were trying to recover the stolen bike.
Irish Times Crime Editor Conor Lally told Newstalk Breakfast they also got the Gardaí involved.
"While they were trying to get the bike back they also rang the Gardaí, and they effectively told the Guards they were tracking the bike and they told the Guardaí where they were," he said.
"The Gardaí also joined this search for the stolen bike.
"All of them ended up on the M50 on the on-ramp, close to Tallaght.
"We believe that the bike was actually recovered by the Guards at the scene, and there was at least one or maybe two arrests carried out there."
Mr Lally said another Garda car then turned up.
"As the party of Brazilian lads and the Guards were stopped on the on-ramp on the M50, a Garda car then arrived at the scene," he said.
"That Garda car crashed into a roadside crash barrier, and in the process of crashing it actually hit this young Brazilian man, 23-year-old João Ferreira and injured his leg."
Conor said Mr Ferreira was then rushed to hospital.
"Such were the extent of the injuries that he had to be taken to hospital, and he's had his right leg amputated from the knee down," he said.
"It sounds like a freak incident."
Protests were subsequently held in Dublin city centre on Monday afternoon.
"They were very angry about what happened; there seems to be a lot of anger generally about their e-bikes and their motorbikes being stolen," Conor said.
"There was a lot of anger over that, and then there was a lot of upset and anger over the fact that João Ferreira had been injured.
"They want an inquiry into what happened, they want that inquiry to happen quickly.
"They also want the Guards to respond in a more active way when their e-bikes and their motorbikes are being stolen," he added.
The Garda Síochána Ombudsman Commission (GSOC) has confirmed an investigation is underway.
A witness appeal has also been issued into the incident.