A specialist Garda team which has been set up to re-examine the murder of Paul Quinn will seek to interview Conor Murphy about his claims that the IRA told him it was not responsible for the shocking crime.
The renewed investigation is due to start next week following an in-depth year-long examination carried out by the Serious Crime Review Team (SCRT).
It is understood that up to 150 potential new lines of inquiry have been identified, which will now be pursued by the hand-picked investigation team.
Senior security sources have revealed that gardaí will make a new bid to interview Mr Murphy.
The Irish Independent has learned that Mr Murphy met investigating gardaí by appointment on one occasion after he made the false claims about Paul Quinn's involvement in crime.
It is understood that the top-ranking Sinn Féin member originally agreed to provide gardaí with answers to "specific questions" that were deemed important to the investigation.
However it is understood Mr Murphy has not met gardaí since that time.
Paul Quinn's parents, Breege and Stephen, have also said on several occasions that the PSNI and Garda confirmed to them that Mr Murphy did not fully co-operate with the original enquiry.
Security sources have said they believe the murder was the work of well-known members of the IRA in South Armagh who have close links to Sinn Féin.
One source said gardaí were satisfied "it was 100pc the work of the IRA", a fact that was also established by the PSNI and the International Monitoring Commission (IMC).
A source familiar with the case said: "The answer as to who was responsible for this crime lies in South Armagh within the ranks of the Republican movement, but they are protecting themselves behind a wall of silence which is just the same as it was during the Troubles."
To date, the Garda investigation has resulted in more than 20 arrests, including Padraig 'Paudie' Treanor, a former driver for Conor Murphy. No one has yet been charged.
Gardaí believe Paul Quinn was targeted by the IRA after he stood up to a number of local Republicans including a senior figure who is heavily involved in organised crime in the area.
The problem came to a head when the murder victim beat this man's son in a fist fight.