Locals in the affluent Castleknock suburb of Dublin say they are shocked at the death of a man in his 30s in the area overnight.
A 34-year-old man who was arrested at the scene is being questioned at Blanchardstown garda station.
Gardaí were called to the house on Beech Park Avenue in Castleknock shortly before 2am today, and discovered the man's body on arrival.
The house remains sealed off this afternoon. State pathologist Dr Marie Cassidy completed a preliminary examination earlier today.
The man's body has now been removed to the city morgue where a full post mortem will be carried out.
"I'm wondering how safe we're ever going to be," said one local man. "Shocked, disgusted…Law and order has broken down in this country," said another.
"It's incredible. Everybody says 'it'll never happen here', but now I'm saying it does happen here. It happens everywhere - it doesn't matter where you live," a local woman added.
So far this year, seven people have died under suspicious circumstances.