Detectives believe morning commuters may have seen the killers behind the country's latest gangland-style shooting.
A 27-year-old man has died after being shot dead close to the Luas line in Kilmainham in Dublin shortly before 10.30am on Monday
The attack was carried out behind apartments at Grand Canal View, near Davitt Road, in an area known locally as the Dry Canal Bed.
It is understood the victim was from the area and was known to gardai. A car was found burnt out at Rialto Court, a short distance away and also close to the Luas line.
Investigators have appealed to anyone who was in the area or travelling through it on the tram between 10am and 11am to get in contact with them.
An incident room has been set up at Kilmainham Garda station. The state pathologist has been asked to attend while Garda forensic experts are carrying out examinations at the scenes.
Garda Commissioner Martin Callinan said early indications suggested a firearm had been found in the burnt-out car. "We will put all the resources that are necessary into bringing this matter to a successful conclusion," he said.
Justice Minister Alan Shatter said it was entirely unacceptable for anyone's life to be taken. "I know the Gardai are doing a very important job targeting individuals engaged in this activity and I hope those responsible are brought to justice," he added.
The victim was originally from St Theresa's Gardens, near the Coombe in Dublin's south inner city, but had a recent address at the nearby The Maltings apartment complex.
Detectives believed the man was a small-time drug dealer and are investigating if his murder was drugs-related.