The Government Chief Whip is calling on Gerry Adams to clarify what he knows about the murder of Brian Stack.
The Chief prison officer at Portlaoise prison was shot by the IRA in 1983 and died 18 months later.
It's emerged the Sinn Féin leader passed on a number of names to the Garda Commissioner earlier this year in connection with the investigation.
Mr Adams claims the names of Sinn Féin members were given to him by the victim's son Austin - something Mr Stack himself denies.
Government Chief Whip is Regina Doherty: "My personal question is if he asked the Garda Comissioner to investigate four of his own people, because he had uncertainty around the allegations and then why did he let them run for general election in February of this year.
"Why did he think that they were fit to stand to represent people?"