The bodies of an elderly couple were discovered in a house in Landscape Park, Churchtown, south Dublin, on Monday night.
Gardaí who were called to the scene found the couple, said to be in their 80s, in the sitting room of the house.
The bodies were examined at the scene by a doctor and it is understood foul play has been ruled out.
Investigations are centring on the possibility that the couple were killed by carbon monoxide poisoning.
Further medical tests are expected.
