A post mortem is due to be carried out today on the body of the 53-year-old man shot dead in Co Wicklow on Wednesday night.
Vincent O'Brien, a small-time drug dealer, was shot several times in the face and upper body at his home in Kilbride Grove in Bray.
Gardaí say there was no evidence of a break-in, suggesting that the victim may have known his killer.
Detectives are examining a number of lines of inquiry, but one possibility under investigation is that the murder was revenge for a recent assault on a more senior criminal in the area.