Gardaí are appealing to the public for information after a 45-year-old man was shot dead yesterday.
Gardaí suspect the murder in Ballymun is connected to a local drugs dispute.
Father-of-two Robert Sheridan was shot dead after he answered the door at his home at Poppintree Crescent at around 11.15pm.
Two gunmen, dressed in dark clothes and with their faces covered, ran from the scene carrying handguns following the attack.
Speaking at the scene today, Superintendent Brian Daly said: "It's understood two armed men involved in the incident left the scene on foot and entered Poppintree Park before exiting onto Willow Park Road.
"We are appealing to anyone who was in the area between 10pm and 12 midnight to contact us here at the incident room at Ballymun Garda Station."
The victim had previous convictions and was known to gardaí as a local drug dealer. He had been formally warned his life was in danger.
Shots had been fired into his home around three weeks ago and the windows were boarded up.
A second area has also been sealed off at nearby Poppintree Park which the gunmen ran through as they fled the scene.
The body of the deceased has been removed to the city morgue for a post-mortem examination.
An incident room has been set up at Ballymun Garda Station.
Detectives are still trying to establish a motive for his murder but it is believed to be linked to a local dispute over drugs and not to either the Hutch-Kinahan feud or another ongoing feud in the area which has so far cost three lives.
Anyone with information is asked to contact Ballymun Garda Station on 01- 6664400 or the Garda Confidential Line on 1800 666 111.