Post mortem examinations have been carried out on the bodies of two men found inside a burnt-out car in Co Louth on Wednesday night.
Gardaí formally upgraded their probe into a murder investigation after Deputy State Pathologist Dr Kahlid Jabbar confirmed the two men had been shot.
However, the results of DNA tests to formally identify the two men are not expected until early next week.
It is believed they were killed as part of a Dublin gang related feud over the illegal drugs business.
Garda search teams spent the day at the scene and carried out searches of the undergrowth and surrounding car park for clues to help identify the killer or killers.
A team of up to 30 detectives and uniformed gardaí, along with officers from the National Bureau of Criminal Investigation are involved in the operation, which is based at Dundalk Garda Station.
The bodies of the two men were found when the emergency services were called to extinguish what appeared to be a car fire.
The Volkswagon golf car had been stolen in Dublin several days ago.
Gardaí believe the two men were from Dublin city and had a number of previous convictions, mainly for relatively minor offences.
