Criminals linked to the Real IRA in Dublin are suspected of murdering a young man in the city.
At least two men who claim connections to the dissident republican terror group are believed by gardai to have had involvement in the shooting of 21-year-old Darren Guerrine.
He was executed in cold blood in Bluebell two years ago, after being lured to his death by a group of men.
The murder remains under garda investigation.
The Real IRA has re-emerged publicly in the Bluebell- Dolphin's Barn area this week, after graffiti threatening drug dealers was scrawled on walls at the Dolphin House housing complex.
The graffiti has raised tensions in the area, amid fears that local drug dealers will be targeted.
The Real IRA has claimed involvement in the murder of drug dealer Gerard Staunton in Cork last January, after issuing an earlier warning that dealers would be targeted.
The dissidents have not claimed involvement in Mr Guerrine's murder, but security sources told the Herald that a least two local dissident republicans, suspected of carrying out illegal protection rackets on car dealers, are suspected of having advance knowledge of the killing.
The 21-year-old victim was reportedly targeted in an argument over drugs, but he was not a major criminal and his death deeply shocked the local community.
One of the two Real IRA men lives in the Bluebell area and is in his late 20s.
According to sources he first came to the notice of the anti-subversive Special Detective Unit in 2006, after the pipe bombing of a property in west Dublin.
This attack is believed to be linked to a protection racket being carried out on a local businessman.