The incident at Wheatfield Avenue was reported to Gardaí at 9.40pm.
He was pronounced dead at the scene. Detectives believe that they had been waiting from about 9pm and that the crime could be related to a local drug dispute.
"I'm unsure at this stage if more people entered the house, we believe however that the confrontation and the shooting happened out on the street", he said.
Gardaí have said that a number of people kicked in the door of Darragh Nugent's house while his children were upstairs.
Independent.ie has learned that the victim was known to gardaí and was previously arrested after a gun and ammunition was discovered in a discarded bag last February.
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He said a number of people were in the area at the time of the shooting, and appealed for anyone with information to come forward.
Gardaí are trying to trace the movements of a large saloon auto that they believe was the getaway vehicle.
"The direction of that vehicle is unknown to us at this stage, but it is very important in our investigation", said Mr Mann.
Anyone with information is asked to contact gardai at Ronastown Garda Station on 01-666 7700.