Up to four vehicles, including the car suspected of being used to deliberately drive over the deceased, have been seized.
The cars are being subjected to a battery of tests, including forensic collision examinations as well as DNA and fingerprint analysis, both inside and outside.
In relation to the car used to drive over the victim, technical experts may be able to capture samples from people who were inside the vehicle, including samples from the steering wheel.
Gardaí are also examining what CCTV footage is available at the two crime scenes involved, as well as those along the possible routes between the scenes.
Mr Reilly suffered a brutal assault, including blade wounds from a machete, before he was driven over by a car, inflicting fatal injuries.
The 36-year-old, thought to have two children, is suspected of having earlier fired shots into a house at Liscarne Gardens, Ronanstown, in north Clondalkin.
Nobody was injured in that shooting, which occurred at around 4am.
Gardaí believe that four to five men, who were in the house at the time, came out and pursued the gunman, who fled in a car.
It is thought that two cars were involved in the high-speed pursuit towards Lucan.
They cornered the car carrying Mr Reilly at the Glebe housing estate in Esker, some 5km away.
Gardaí believe some six men, possibly more, were involved in a row at the scene, in which Mr Reilly was beaten and slashed, then crushed under a car.
Gardaí said he had suffered “substantial injuries” before being brought to James Connolly Memorial Hospital in Blanchardstown, where he was pronounced dead at 5.30am.
Sources said the attackers seemed to have been consumed with revenge without fearing the consequences.
“Obviously a veil of rage came down on them with the shooting and they lost all sense,” said a garda source. “They were just focused on getting him. They didn’t think about getting caught.”
Mr Reilly, who lived in St Finian’s Close, near where he was killed, had recently served, with standard remission, a seven-year sentence for drugs supply, imposed in 2011.
While a known drug dealer locally, he was not considered a major player. Gardaí, who are trying to locate the gang who pursued him, are examining if some drugs-related row forms the background to the murder.