The Fianna Fáil leader says Gerry Adams is using the peace process as an excuse not to tell the truth about the murder of Brian Stack.

Portlaoise prison officer Brian Stack was fatally shot by the IRA in the 1980s.

The Sinn Féin head claims he was given names connected to the case by Mr Stack's son Austin - something the family denies.

Gerry Adams made a personal statement in the Dáil yesterday evening insisting Austin had "changed his story".

Deputy Adams says the names he gave to the Garda Commissioner in connection with the murder were passed on by the victim's son - something Austin Stack has denied.

Following Mr Adams' statement, Sinn Féin deputies Martin Ferris and Dessie Ellis denied having any involvement in Mr Stack's death - after being named under Dáil privilege by Deputy Alan Farrell.

During his 10 minute speech, Deputy Adams stressed that he never named anyone as a suspect in the e-mail to Noirin O'Sullivan.

Mr Adams said during his statement: "My generation of republican activists who lived through and survived the war have a responsibility to try and bring the families of victims of the war, irrespective of who was responsible, to a better place.

"That is what I have tried to do with my engagement in 2013 with the Stack Family."

Speaking to Newstalk Breakfast, Michéal Martin said the Sinn Fein leader definitely has knowledge that would help the Gardai if he really wanted to get justice for the prison officer who was killed by the IRA.

Mr Martin argued: "I think his statement is unsatisfactory, because essentially he's making it clear he is not going to provide the name of the individual he brought the two stack sons to.

"The key point is how do we get those who were responsible for the murder of Brian Stack brought to justice - that's the core issue. There's a lot of fog, and Gerry Adams wrapped up a lot of the issues in the peace process, deliberately in my view to avoid that core question."

"Sinister Miss Marple"

Meanwhile, Máiría Cahill has called the Stack controversy a case of 'deja vu' for Sinn Féin, and suggested the party's leader has acted like "a sinister Miss Marple".

The former Labour Senator, who claims to have been sexually abused by an IRA member, says Gerry Adams is interfering in the Brian Stack murder inquiry in the same way he interfered in her alleged rape.

Speaking on Newstalk Breakfast this morning, Máiría Cahill said: "I don't think it was helpful that people were named in the Dáil, because it deflects from the one person who did carry out an investigation.

"The one name that isn't in that email to Noirín O'Sullivan is the name of the senior IRA leader who Gerry Adams took the Stack family in a blacked out van to meet".

She added: "I think it's a case of deja vu and here we go again [...] I really felt for Austin Stack because Adams quite spectacularly managed to blame the victim in this case, and he took on the victim mantle himself.

"While it isn't surprising for me, I think it could be quite shocking for other people having to watch that - particularly Austin Stack and his brother Oliver".

On the subject of Gerry Adams, Máiría said: "He went to an IRA leader who he trusted, and drove in a blacked out van like some sort of sinister Miss Marple trying to uncover information which he said he believed would help the Stack family."

She also suggested: "Clearly someone knows who murdered Brian Stack and they know who hasn't come forward with that information."