The purported claims by the Continuity IRA (CIRA) included threats to carry out further attacks on “drug dealers and criminals”.
The attack at the Regency Hotel by a gang of at least six men, three armed with AK-47s and dressed in Garda-type uniforms, left Dublin criminal David Byrne dead.
Detectives suspect the murder of Byrne, a senior member of the Kinahan crime syndicate, was in retaliation for the shooting dead of Gary Hutch in southern Spain last September.
Gardaí are treating the CIRA claims “with caution” given the reasons cited in its statement of responsibility.
Some sources also expressed doubt over CIRA’s ability to launch such an attack in Dublin, at least on its own. This has led to suggestions that it might have acted with a criminal gang, and perhaps took credit to mask the gang’s role.
The claim of responsibility was issued to BBC Northern Ireland and used a known code word. It is understood the claim came from someone seen as a senior source in the CIRA leadership.
Efforts by theto seek verification or knowledge about the claim was hampered, in part, by the fact that the CIRA — and political groupings linked to it — have been riven with disputes and splits.
Republican Sinn Féin (RSF), the political organisation traditionally aligned with CIRA, said it had “no knowledge” of the claim and said as far as it was concerned, it was “not the Continuity IRA”.
Several RSF spokesmen said there was another grouping — which included splinter elements — that used the CIRA name.
Some 10 people linked to this section — including people on both sides of the border — were arrested, charged, and bailed for alleged terror offences in the North in November 2014.
Efforts to contact Continuity Sinn Féin, which is thought to be politically aligned to this group, were unsuccessful.
The statement issued to the BBC said that “a unit of the CIRA was authorised to carry out an operation in Dublin at the weekend”.
It said Byrne was involved in the murder of Alan Ryan in Dublin four years ago.
Ryan was the head of a separate dissident group — a Real IRA faction — when he was murdered by two north Dublin drug traffickers.
The statement said that while Ryan was not a member of CIRA, it was not going to allow criminals to target republicans.
It stated: “This will not be an isolated incident. CIRA units have been authorised to carry out further operations.”
Garda bosses are treating the claim “with caution”, but said they would examine it.
“We will look closely at this,” said one senior source, “but Alan Ryan was RIRA and as regards David Byrne there’s nothing to support his involvement.”
Byrne was a member of a southside criminal group and had no part in the network that killed Ryan.
Sinn Féin leader Gerry Adams said he believed the ‘CIRA group’ had both him and other Sinn Féin reps “under active death threat”.