Two people arrested in connection with the death of a man at a house on the North Circular Road have been released without charge.
Gary O'Brien was found with a single gun-shot wound to his forehead earlier this month. Gardai initially thought Gary O'Brien may have killed himself, but after tests they launched a murder investigation.
The 51-year-old died from a single gun-shot wound to his forehead, but the gun hasn't been found.
A man and a woman in their 30s were arrested the day after, but they've now been released from questioning.
Investigators are appealing for anyone with information about what happened the night Gary O'Brien died to get in contact.