The body of the man, who was in his 30s, was found at a house in Ballybofey on Saturday morning.
The man has been named locally as James Devlin who was originally from Glasgow but has lived in the area for a number of years.
It is understood that Mr Devlin, who was aged 35, had been at a house party at the house earlier in the evening.
The house at Cappry, Ballybofey has been sealed off and a full Garda investigation has been launched.
The man’s body was taken to Letterkenny University Hospital for a postmortem due to take place today.
Meanwhile, an 18-year-old found dead in a field has been described as a quiet, shy and respectful young man.
Tributes were paid to Cameron Reilly as gardaí continue their investigation after his body was discovered in a field in Dunleer, Co Louth.
While gardaí are not revealing details of the post mortem, it is believed he sustained serious injuries to his neck.
His body was found on Saturday by a man walking his dog at Shamrock Hill, near the town’s Glen Dimplex factory.
Gardaí sealed off the area and his body was taken to Our Lady of Lourdes Hospital in Drogheda for a post mortem. While details of the findings are not being disclosed, gardaí confirmed he died in violent circumstances.
Gardaí carried out house-to-house inquiries in the area and are appealing to anyone who was in his company or with information about his movements on Friday evening and Saturday morning to make contact.
Gardaí are also appealing to anyone with dashcam footage recorded in the Dunleer area to make it available to them.
Inspector John O’Flaherty said investigators are particularly appealing for help locating Cameron’s phone, an Apple iPhone 8X (64GB) with a green hardback cover, space grey in colour.
“We would ask home and business owners in Dunleer to check their property, including wheelie bins and waste skips. We would also ask anyone offered a phone for sale as described to contact us,” he said.