Gardaí have questioned a man in connection with yesterday's hit-and-run on the main Cork-Waterford road near Carrigtwohill in County Cork, in which a 35-year old father of eight was killed.
They have also examined a car that is believed to have been involved in the collision.
Both developments are believed to be significant in the garda investigation.
Gardaí continue to appeal to people who were on the N25 dual carriageway in the Cobh Cross and Carrigtwohill areas between 1.30am and 2am yesterday morning.
They also want to speak to people who were on the Fota Road, between Cobh Cross and Belvelly Bridge.
They are particularly anxious to hear from motorists who may have dashcam footage from that time.
The dead man has been named as Michael Burke, who had an address in Midleton in Co Cork, but who was originally from the Blackpool area of Cork City.
He is survived by his wife, eight children, his mother and family. He was recently pre-deceased by his father.
Mr Burke is believed to have begun walking from Cobh Cross towards Cork City after he had a minor collision in his own car on the Fota Road.
He was found in a serious condition by gardaí on the west-bound carriageway of the N25. He was pronounced dead at the scene.