FIRST minister Peter Robinson has warned that if the IRA is behind the killing of Kevin McGuigan, Sinn Féin will be expelled from the executive.
He was speaking following speculation that mainstream republicans carried out the Short Strand murder on Wednesday night.
The Provisional IRA has been on ceasefire since 1997 and decommissioned its weapons in 2005.
Mr McGuigan, a former IRA prisoner is understood to have fallen out with the organisation and was a suspect in the murder of former IRA leader Gerard 'Jock' Davison in the nearby Markets area of Belfast three months ago.
"Obviously we want to let the PSNI carry out their investigations but we will want to talk to the police to establish whether there is any organisational involvement from the Provisional IRA, whether there was any decision that links the events of last night to the republican movement," the DUP leader said.
"If there is there will be repercussions. Legislation sets out the steps that should be taken but if any organisation has gone back on its ceasefire then very clearly there is no place for their representatives to be in the Executive of Northern Ireland and they should be expelled from it."
Mr Robinson said it was "atrocious that people think they can take the law into their own hands and dispense justice as they see it".
Sinn Féin South Belfast assembly member Alex Maskey said he has "no concerns about any IRA involvement in this whatsoever" and branded speculation "unhelpful and unwelcome".
"We met the PSNI today to impress on them the need for a thorough and adequately resourced investigation into the killing of Kevin McGuigan," he said.
"There can be no place for such actions on our streets and in our community. I would call on everyone in the local community to assist the police investigation into this fatal shooting."
SDLP leader Alasdair McDonnell, who knows the family, said they "are in grief this morning, because somebody took it on themselves to kill".
"Many of these organisations have wound down and effectively gone out of existence, the difficulty you have though is the people involved haven't gone out of existence," he said
"People who have the capacity to kill and maim and murder 20 years ago still have that capacity.
"Anybody who has any evidence as to what was going on here should put it in the hands of the police, they are the only organisation authorised to deal with murder and the breaking of the law."
