DETECTIVES are closing in on Mr Z -- the gangland killer who murdered Tallaght man Stephen O'Halloran.
Descriptions of the mystery hitman were given at the trial of David Patchell, who was convicted of murdering O'Halloran in a cold-blooded gangland hit in Tallaght two years ago.
The killer has not been charged with murder -- but gardai are aware of his identity and he may yet face the courts.
The jury at Patchell's murder trial heard how the unnamed hitman fired seven shots during the murder of Stephen O'Halloran and the wounding of two of his friends on the night of January 19, 2009.
The shooter used his left hand -- as his right was in plaster.
Patchell, from Rossfield Crescent, Tallaght, this week began a life sentence for the murder. The chilling build-up to the hit was revealed during his trial.
Mr Z was one of three men who were in a car earlier on the night of the killing with Patchell as they toured the Tallaght area looking for their target, Mr O'Halloran.
In court the three with Patchell were initially only identified as X, Y and Z.
It was later revealed by defence counsel Brendan Grehan that X was 21-year-old Paul Byrne who went missing on July 15 2009 -- six months after the murder.
His body was found in the Dublin Mountains on Thursday July 29, 2010.
Det Garda David Jennings was told by Patchell that he (Patchell), Paul Byrne and Y were supplied with new SIM cards for mobile phones on the day before the shooting. Y was never named.
Mr Z only joined the others in the car at a late stage on that night.
He had seven bullets in his Glock while Patchell's had only three.
A bogus arrangement had been made by phone to join Mr O'Halloran for "a sniff" of cocaine.
Patchell said there was no plan, and that he had never fired a gun before.
He claimed to have carried out the shooting to clear a €5,000 debt after he was threatened by a gang who blamed him for losing cocaine.
The hitman Mr Z was the last person to get into the car -- the court heard that he was smaller than Patchell and physically "unremarkable".
They were dropped off and made their way to Kilmartin Drive on foot.
They crept up, sidling along the wall, before opening fire on either side of the Renault in the driveway of Mr O'Halloran's home.
Mr Z fired with his left hand as his right hand was in plaster.
Mr O'Halloran died at the scene while the two passengers, Paul Core and Anthony Harte survived, despite being wounded twice.
After the deadly attack on Mr O'Halloran, Patchell said he called Paul Byrne and Mr Y, as well as his girlfriend Rachel Hall and Paul Byrne's girlfriend Martina McQuillan.
Patchell eventually -- in his 13th interview -- told Det Garda Padraig Mullarkey the identity of Mr Z.
But he pleaded with him not to reveal this until his parents were "safe" and out of Tallaght.
He said he was afraid of the hitman and his gang.
Ironically, victim Stephen O'Halloran's mother, Samantha Dunne, told the Central Criminal Court that she and her family had left Tallaght on the night of the murder "with just the clothes on our backs".
They have never returned to Tallaght.