Republicans from across Ireland are expected to travel to Dublin later this week for the funeral of Vinny Ryan, brother of murdered Real IRA boss Alan Ryan.
The 25-year-old died in hospital on Monday night after being shot in the head in a drive-by attack outside a house in the Finglas area of the city.
The murder is being linked to a long-standing feud between the Real IRA in Dublin and a major drugs gang.
Sources say the victim was sitting in car, having dropped off his partner and his two-month-old baby girl, when he was targeted.
He had previously been warned he was under threat from criminal elements and survived an attempt on his life in October when he was stabbed in the neck as he walked through Parnell Square in north Dublin with his then pregnant girlfriend.
The same gang responsible for the murder of his older brother Alan in 2012 are also thought to have been behind the shooting of Ryan's close associate, west Belfast man Deccy Smith, who shot outside his child's crèche in the Hollywell Avenue area of Donaghmede in March 2014.
Smith had been living in the capital having fled Belfast following the savage double murder of republicans Joe Jones and Eddie Burns in 2007.
The car used in the shooting of Vinny Ryan was set on fire close to the Victoria bridge area on the Naas to Rathangan road.
The 25-year-old is expected to receive a paramilitary-style funeral with republicans from across Ireland to attend.
There was criticism of gardaí for failing to intervene during the funeral of his brother in 2012, when men and women in combat uniform with masks and sunglasses accompanied the cortège to Holy Trinity Church in Donaghmede, where Requiem Mass will also be held for Vinny Ryan later this week.
A volley of shots was also fired in the hours before the funeral.
Prominent Lurgan republican Colin Duffy gave an oration at the graveside of Alan Ryan.
While he is currently on bail charged with a gun attack on the PSNI, he is not allowed to leave the jurisdiction.