Detectives have identified the Real IRA gunmen they believe murdered Belfast father-of-five Danny McGurk.
They also picked out a terror chief who allegedly organised the killing which followed a fall-out between Mr McGurk, 35, and the renegade grouping behind the Omagh bomb atrocity.
All three have been questioned, although no-one has been charged with the shooting.
Police are understood to be ready to offer witness protection scheme places in a bid to end the silence.
But Mr McGurk’s mother Mary claimed no one would be brought to justice. She declared: “Witnesses are too frightened to come forward because they fear they will end up dead the next day.”
It has also emerged that hours after the August attack Provisional IRA men went into a bar and ordered several dissident rivals to leave.
Up to nine people have been questioned by police who seized four cars thought to belong to the suspects. Some have been accused of weapons and explosives offences linked to the investigation.
The vehicles are being examined by forensic experts in a bid to make a breakthrough in the three-month inquiry.
Mr McGurk was shot five times when he opened the door of his Lower Falls district home to two gunmen and a third terrorist suspect.
His children were playing in the Ross Road house at the time of the shooting, which ended a bitter week-long feud.
The detective heading up the probe, Superintendent Hugo Frew, today insisted the Real IRA was to blame.
He said: “We have interviewed everyone we have identified as being connected with an incident the week before or the murder itself.
“I believe I know who carried out this crime; we have very firm suspects for this murder.”
Even though Mr McGurk had no paramilitary connections, he had clashed with Real IRA men policing the neighbourhood.
When the dissidents called at a relative’s house over claims someone had been urinating in a driveway in the area he told them to leave.
But two car loads of men soon returned and savagely beat him with hammers and wheel braces.
As soon as Mr McGurk was released from hospital he went looking for revenge, armed with a knife.
He failed to track down his attackers, but they learned of his intentions and decided he had to be shot.
The killing ignited fears Provisionals may hunt down the dissidents blamed for the shooting. Graffiti naming the chief suspects has even appeared in parts of west Belfast.
One security source disclosed: “Later on the day (of the shooting) there would have been a confrontation in a local bar between rival republicans.
“As a result of that confrontation the Real IRA members left the bar, so you can guess where the balance of power lies.”
Detectives who returned to the murder scene to carry out house-to-house inquiries admit potential witnesses could be too frightened to speak to police.
Mr Frew said: “I can fully understand why people living in that area would be afraid to come forward.
“We are not in the business of forcing people to become witnesses.”
Despite the police determination to catch the murderers, Mrs McGurk insisted their efforts would be in vain.
At her west Belfast home close to the Royal Victoria Hospital the 74-year-old said: “I want justice, but there is a wall of silence.
“The murderers won’t be caught unless someone has a guilty conscience and gives themselves up to police.
“Why haven’t these people at least claimed it or given us a reason why they did it?
“Speak to me, and tell me. Or are they too ashamed?”