Gardaí believe a Mayo pensioner found dead in the driveway of his home was struck by a vehicle in the spot where his remains were found early on Sunday afternoon.
Senior Garda sources said they were following a definite line of inquiry. However, they have yet to determine if the crash in which the man was killed was accidental.
The victim has been named as John Gaughan, a 72-year-old bachelor, who lived alone in a house overlooking the Atlantic at Glosh, Blacksod, on the Erris peninsula, Co Mayo.
The alarm was raised at about 12.20pm on Sunday when a neighbour spotted Mr Gaughan's body lying in the driveway to his home.
He was last seen alive on Saturday night when he went socialising in nearby Binghamstown village. Gardaí believe he was given a lift home by a man from the area known to him.
They are hopeful that this man may be able to help them piece together Mr Gaughan's last movements and possibly the circumstances leading to his death.
Gardaí say the results of the postmortem and examinations of the scene by the Garda Technical Bureau reveal that Mr Gaughan was fatally struck by a vehicle in his own driveway.
They have now discounted the theory that he was struck on the roadway by a passing vehicle and collapsed and died while trying to make his way into his house.
Gardaí say they are hopeful of an early breakthrough in the investigation into Mr Gaughan's death.
One local source said Mr Gaughan was "hugely popular and respected", adding the community had been "numbed" by his death.
"He was the kind of fella who would do anything for you," said the source.
State Pathologist Dr Marie Cassidy travelled to Castlebar General Hospital on Sunday to carry out a postmortem.
While the results have not been publicly revealed, The Irish Times understands it concluded Mr Gaughan was struck by a vehicle.
The death is being treated as suspicious rather than as a fatal traffic accident.
The investigation is being headed by Supt Joe Gannon, the district officer for Belmullet.
Gardaí in the area were continuing door-to-door inquiries yesterday in an effort to establish if any locals saw Mr Gaughan being driven home on Saturday night.
Gardaí have appealed for information from anyone who was in the area of the house at Blacksod or anyone who saw the deceased from 8pm on Saturday until the discovery of his body at 12.20pm on Sunday.
Gardaí are also anxious to determine whose company Mr Gaughan was in while socialising on Saturday night.
Anyone with information is asked to contact Belmullet Garda station on 097-81910.