Gardai have upgraded their investigation into the death of a man at a flat on the North Circular Road. Detectives now believe Gary O'Brien from Finglas was murdered.
The 51 year old died as a result of a single gun-shot wound to his forehead on Sunday night. He was a father and grandfather and had lived in the area for seven years. He had limited mobility.
It had been originally thought that the wound was self inflicted but two people have now been arrested.
A man and a woman in their 30s are being held at stations in the city centre. Gardai are appealing for anyone with information on the murder to come forward.
Superintendent Ann Markey from the Bridewell Garda Station said "There are a number of residents within the locality here and within the local community and people who pass by here everyday and we would really ask them for their co-operation."
"We are asking them if they saw anything suspicious or any activity that they found unusual between Sunday night at 8pm and Monday morning at 6am from the vicinity of O'Devaney Gardens Gardens to Aughrim Street in Dublin 7", she added.
"It is quite a stretch but anyone we would like to speak to anyone who feels they saw anything unusual in that time."
"There is a lot of traffic that passes through here like buses and taxis. I’m asking anyone who saw anything or feel they saw something suspicious to call us on on 01 666 8200 or to call any garda station."
Technical officers have been examining the scene all day. The weapon used in the shooting still hasn't been located.