The man, aged 55, was shot a number of times after answering the door to the gunman at his home in Croftwood Park.
The gunman is thought to have fled the scene in a blue Ford Fiesta, which was later found burned out on Le Fanu Drive before being picked up by a silver Skoda Octavia and travelling to Monksfield Walk where the Skoda was also found burned out.
Gardaí are now appealing for information regarding a third car, a black Toyota Avensis, registration number 10-D-123251, which may have been seen in the Woodford Walk area between 10.57am and 11.06am yesterday morning.
The Avensis has since been found burned out on Peamount Road.
Gardaí are asking anyone who was in the area between 10am and 9.30pm yesterday, who may have seen, or has any information about the car, to contact them at Ballyfermot Garda Station on 01 666 7200, the Garda Confidential Line 1800 666 111 or any Garda Station.
