Gardai are probing whether a small-time gangster was shot dead for his suspected involvement in the murder of Mark 'Guinea Pig' Desmond in December 2016.
David Lynch was targeted as he left his home in Foxdene Avenue, Clondalkin, shortly after 2pm on Friday.
He was shot a number of times in the head and neck and was pronounced dead at the scene.
Gardai suspect that an expierenced hitman was involved due to the nature of the shooting, and the way the two vehicles used were disposed of.
Detectives are probing a number of possible motives for the killing, and are investigating whether Lynch was targeted by associates of his former pal, notorious gangster Desmond, who died in a brutal gangland execution on December 2, 2016.
Desmond (41) was shot dead at Griffeen Valley Park in Lucan, west Dublin.
He died from multiple gunshot wounds to the head, chest and groin.
Lynch was suspected of "logistical" involvement in that killing.
However, gardai have stressed that this is only one line of inquiry.
Lynch's links with several criminals in Kildare and Dublin could also have made him a target for several organised criminal gangs.
The 42-year-old was repeatedly shot by the gunmen and died at the scene.
He was closely connected to a number of major criminals across Dublin and Kildare but kept a low profile and had no major criminal convictions.
Following Lynch's murder, his killer fled the scene in a white van, which was found burnt out a short distance away outside Lucan National Community School.
A firearm with a silencer attached was discovered beside the van.
Dozens of children on their way home from school saw Lynch's dead body lying in the road.
Superintendent Paul Doran, of Lucan Garda Station, said: "It was a cold, callous crime on a busy day with a man going about his business in a residential area.
"It's a cause of serious concern to An Garda Siochana.
"We do have patrols in the area and areas close by. I would be revisiting those patrols to alleviate public concerns."