By Fiachra Ó Cionnaith, Political Correspondent
Labour leader Brendan Howlin has warned there "can't be a separate rule for Gerry Adams" after growing calls were made for the Sinn Féin leader to provide full information to gardaí on the 1983 murder of prison officer Brian Stack.
Speaking to reporters after Mr Stack's son, Austin, interrupted a Sinn Féin Brexit press conference to accuse Mr Adams of withholding information on the murder, Mr Howlin said if Sinn Féin wants to be a credible party it must comply with legal norms.
While stopping short of saying Mr Adams' position as a TD and party leader is untenable if he refuses to provide further details to gardai, Mr Howlin said until this takes place Sinn Féin will be "apart from the rest".
And in a clear warning to his opposition rival, he added that there "can't be a separate rule for Gerry Adams" when it comes to knowledge of murders during the Troubles.
"The statement made by Gerry Adams yesterday in the Dáil was no surprise to anybody.
"Faced with the grim realities of his own past he often blows smoke, in fact tries to make himself a victim.
"It's crystal clear to all of us who met the Stack family, who are trying to get truth for that family, that Gerry Adams certainly knows the identity of the IRA commander that he tasked in investigating the facts surrounding the murder of Brian Stack and he should give that identity to an garda siochana.
"Those of us who have met with the Stack family believe them. They are entitled to know the truth.
I believe he knows the identity of the murderer, and I think he should bring that identity to An Garda Síochána in addition to all he knows.
"This notion now that somehow this makes the peace process more vulnerable to tell the truth, when he demands the truth from so many other people, is unacceptable and simply unsustainable.
"There can't be a separate rule for Gerry Adams," he said.
Mr Howlin said while Labour remains committed to co-operating with "any progressive parties", the reality is "you cannot be a slightly constitutional party" and that Sinn Féin must now "embrace the parliamentary process and the responsibilities" they have when it comes to transparency in a democracy.
Asked if this means Mr Adams' position as a TD and leader is untenable, Mr Howlin said Sinn Féin needs to "make up their minds" on where the party's future lies.
"If Sinn Féin want to fully embrace the parliamentary process they have to have the same responsibilities as any other leader of a party.
"Can you imagine any other party leader standing up in the Dáil yesterday with information on the murderer of a servant of this state and not being required to give full frank and complete information?
"Sinn Féin will have to make up their minds on whether they want to embrace the parliamentary system and all the responsibilities that go with it.
"They're certainly not providing full information…It is my belief that Gerry Adams certainly knows the identity of the murderer of Brian Stack and he should bring that to the attention of An Garda Síochána immediately, and until such time as the norms of parliamentary activity, the norms of conduct apply to Sinn Féin they will be apart from the rest," the Labour leader said.