GARDAI are now satisfied that the murder of serial burglar Christopher Warren was a punishment attack that went wrong.
Detectives have ruled out suggestions that 35-year-old Warren could have been the victim of a gangland hit.
They believe the shooting was linked to an incident that occurred at a premises in Inchicore, south-west Dublin, on St Stephen's Day night.
Warren is alleged to have hit a woman in the premises during a row that apparently erupted over drugs.
A group of men are understood to have planned to abduct him on Friday night and carry out a punishment attack in revenge for the earlier incident.
It is not yet clear whether they had intended to shoot him in the legs or to beat him up.
But Warren either spotted the gun while he was in a car with his attackers and tried to make his escape, or he started struggling with them.
He was shot between the stomach and chest and also in the lower leg at Constitution Hill in the north inner city.
A friend of Warren was in the area and took him to St James's Hospital in a blue Mercedes car, which was later found around a mile away in Cork Street.
Warren was left lying outside the accident and emergency unit shortly before 9pm and was rushed inside for treatment.
However, surgeons were unable to save him and he was pronounced dead shortly afterwards. In the meantime, gardai had been alerted and quickly found the abandoned Mercedes. No apparent attempt had been made to burn it.
Gardai initially interviewed a man about the car, and then in the early hours of Saturday he was arrested for questioning under section 50 of the Criminal Justice Act, 2007, which allows him to be held without charge for up to seven days.
He was quizzed by detectives throughout the weekend at Kevin Street garda station after his initial period of detention had been extended. Late last night he was released without charge.
Forensic tests were also carried out on the Mercedes, which had blood stains on the back seat, and also on ammunition shells that were recovered during inquiries to establish the calibre of the weapon used.
Gardai expect to make further arrests in the coming days as their inquiries are extended throughout the city. The man currently being questioned is from the northside. However, gardai believe several of those involved in the attack are from the south inner city.
Warren, who was on temporary release from prison for Christmas, was a prolific housebreaker and a prime target of Operation Acer, which was set up last March to crack down on burglaries in the capital.
Acer is feeding into the nationwide operation, codenamed Fiacla, which has been successful in curbing a worrying rise in burglaries over the past two years.
Warren is known to have been drinking with friends in the Cork Street area earlier on Friday, and gardai have been trying to contact those who had been in his company at any time of the day.
Warren's younger brother, Paul (24), was one of the first victims of the Crumlin/Drimnagh gang feud when he was shot dead in a south inner city pub in February 2004.