JOHN Gilligan has been "shaking down" former associates for cash, gardai believe.
The gangster is suspected of threatening a number of people before a botched gun attack on his life.
The pint-sized criminal was drinking in another pub a short distance away when a gunman entered the Halfway House on the Navan Road.
As he was officially warned of a threat to his life, Gilligan dismissed the incident as a "Halloween prank".
However, gardai are now probing underworld reports that Gilligan has been "shaking down a number of former associates for cash".
"It's possible this happened because of Gilligan's arrogant behaviour since he came out," a source explained.
Gardai have a massive list of potential suspects whom they believe want to murder the gang boss who was released from prison in October.
Among the possible crimelords who want Gilligan shot dead are international drugs traffickers George 'The Penguin' Mitchell and Christy Kinahan who are based in Holland and Spain.
Also in the frame is Gilligan's former right-hand man -- jailed killer Brian Meehan -- who is serving a life sentence for the murder of reporter Veronica Guerin and who had been feuding with Gilligan for a number of years.
Following the failed attack, Gilligan was given security advice by gardai while in the High Court for legal proceedings regarding his former property, Jessbrook, yesterday.
A source explained: "While it is most likely that one of Gilligan's old enemies ordered this, it is also possible that this happened because of Gilligan's arrogant behaviour since he came out.
"Information has come in that he has been personally calling to the doors of people all over the city that he perceives owe him money and this could be another reason why someone would want him dead.
"The list of people that want Gilligan dead is as long as a piece of string but there is no doubt that if he keeps shaking down people for cash, he will end up dead very soon.
"This is very much unlikely to be a dissident republican issue, far more likely to be an organised crime issue, but at the end of the day the would-be assassin went to the wrong pub."
Gilligan attended the High Court yesterday where the Criminal Assets Bureau wants the court to strike out a potential legal impediment to the sale of property seized from Gilligan and his family.
Speaking outside the court, Gilligan said: "I'm doing grand. I just think it was a Halloween prank, too late. I've no problem with anybody and I've no fear of anybody. No problem whatsoever and I've no enemies."
And the Herald has learnt that in a bizarre move, the deluded criminal started mouthing outside court that the Criminal Assets Bureau were responsible for the failed murder attempt.
"It looks like he has gone mad -- can he not keep his trap shut? What a stupid thing to say," a source pointed out.
Shortly after the court hearing, Gilligan was officially warned by gardai of the threat against his life and given advice on his personal security, a senior source has revealed.
This followed the incident in the Castleknock pub in which a raider armed with a 9mm handgun entered the Halfway House looking for the gangster who was drinking with his son, Darren, in a nearby Hole in the Wall pub.
The gunman entered the Halfway House pub reportedly saying "where's Gilligan, where's Gilligan?"
After failing to find his target, the bungling hitman left and was pursued by armed gardai, dropping his loaded handgun on the River Road in Finglas, before fleeing on foot after he discarded his bike.