Gardaí in Buncrana in Co Donegal are investigating the discovery of the body of a man and a woman in their 70s at a house in Carndonagh.
The discovery was made shortly after 9am today.
A man in his 40s was arrested a short time later. He is being held under section 4 of the Criminal Justice Act
The State Pathologist's Office has been notified.
The scene has been preserved and a technical examination will take place.