Slieve League in County Donegal remains closed to the public as Gardaí try and track down the family of a man who has been missing since last weekend.
Gardaí believe the man may have been the victim of a serious assault and they are treating the investigation as a potential murder case.
The man is believed to be in his mid-60s and originally from Northern Ireland.
Investigators are liaising with police in Northern Ireland in a bid to determine his whereabouts and are working to make contact with his family.
Reports yesterday suggested forensic teams are examining a 'blood-spattered' car which was discovered as part of the investigation.
At this stage, nobody has come forward to report the man as missing.
Slieve League in Co Donegal remains closed to the public this morning.
This is the fourth day in a row that the popular tourist destination has been closed.
Gardaí have appealed for witnesses or anyone with any information to come forward.
They are particularly interested in talking to people who were in the area between Saturday evening and Sunday evening and may have camera footage.
Slieve League or Slieve Liag is a mountain on the Donegal coast that boasts some of the highest sea cliffs in Europe.