Gardaí are awaiting the results of toxicology tests to determine the cause of death of a 20-year-old man in Co Donegal at the weekend.
A postmortem on the body of Thomas Sheridan was inconclusive, gardaí said last night.
Mr Sheridan collapsed as he was being driven to his home in O'Maolchonaire Avenue, Donegal town, on Sunday afternoon.
Attempts to revive him at the house failed and he was rushed to Letterkenny General Hospital where he was pronounced dead on arrival.
Detectives visited a remote shebeen yesterday afternoon known locally as "the bog hotel" to check reports that it was one of a number of locations visited by the young man.
Gardaí said they have questioned a number of people in their efforts to trace the young man's movements between late Saturday night and 1.30pm on Sunday.
Supt John Dennedy said gardaí were satisfied they knew where the young man was up to 8am on Sunday.
He added: "There are some gaps from then until 1.30pm and I would appeal to anybody who may have helpful information to contact the gardaí."
Mr Sheridan, an unemployed labourer, is known to have attended a house party in the Mountcharles-Inver area.
The shebeen - off the road linking Frosses and Glenties - was included in the investigation because there was a reported sighting there of the van which took Mr Sheridan to his parents' home.
Garda sources said there was no immediate evidence to link the shebeen to Mr Sheridan's death.
It's known locally as "the bog hotel" because of its location and because it has been the scene of clandestine drinks parties.
The test results are expected to be known in a couple of weeks.