Post-mortem examinations are due to be carried out on Friday.
Gardaí are continuing to investigate all circumstances into the discovery of two bodies at a house in Donegal on Thursday, 23 December.
The bodies of two men were found at a residence in Windyhall, Letterkenny.
One of the bodies; a man aged in his 80s, was discovered in the house.
The second body; a man aged in his 50s, was found in a car in an adjacent shed.
The men have been named locally as Daniel Duffy and his son Damien Duffy.
RTÉ News reports that the incident is being treated as a murder-suicide.
No weapons were discovered at the house and a spokesperson for An Garda Síochána has confirmed that no firearm was used in the incident.
Both bodies have been removed from the scene and taken to Letterkenny University Hospital where post-mortem examinations are scheduled to take place on Friday.
The results of the post-mortems will determine the course of the investigation.
As of Friday morning, the scene remains preserved as the Garda Technical Bureau carries out further examinations.
Gardaí are appealing to anyone who may have relevant information in relation to the incident to contact them at Letterkenny Garda Station on 074 916 7100, the Garda Confidential Line or any Garda Station.
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