The R238 Ballyliffin to Clonmany road remained closed for most of yesterday at Annagh Crossroads.
Garda investigators were at the scene for most of the day following an incident there shortly after 10.30pm on Sunday night.
According to local sources, the incident involved a garda patrol car and two pedestrians.
One of the pedestrians, the local source confirmed, was taken by ambulance to Letterkenny General Hospital.
A garda spokesperson would not comment on the matter as it had been passed to the Police Ombudsman for further investigation.