Sinn Féin president Gerry Adams and the family of murdered prison officer Brian Stack are in dispute surrounding the facts of the case.
Each is insisting theirs is an accurate reflection of their knowledge of the 1983 killing ,which is the only recorded murder of a prison officer in the State.
Both sides agree on three crucial points. The first is that the murder was wrong and should never have happened.
The second is that Mr Stack's sons, Austin and Oliver, went with Mr Adams in 2013 to meet a senior IRA figure at an undisclosed location.
The third point is that the meeting was arranged by mutual consent and a confidentiality agreement was in place.
However, the content of the conversation remains a point of contention.
Austin Stack said the senior IRA figure told him and his brother the organisation had killed their father. He said they were told the perpetrators were still alive, and the person who ordered the murder had been disciplined.
Mr Adams said the IRA figure did not tell them if the person who killed Mr Stack was alive or not.
"Austin Stack has said the individual we met told us he met the perpetrators, he didn't tell us that. Austin Stack also said he told us that they were alive, he didn't tell us that," he told RTÉ Radio. "What he told us was contained in a tight statement which was given to the Stack brothers, which they then wrote down and they then asked him a number of questions. I took very little part in the discussion.
“He never said he know who killed Brian Stack – he said that he had information that the IRA was involved and then he explained that.”
The location of the meeting is also in dispute. The Stack family say they were told it took place south of the Border. However, Mr Adams told the Dáil this week it took place in Northern Ireland.
Both acknowledge a confidentiality agreement was in place, but each side accuses the other of breaching it first.
The Stack family and Mr Adams also differ on a number of other aspects, including the origin of four names which the Sinn Féin president said he gave to the Garda Commissioner this year. They include
Mr Stack says he did not give those names to Mr Adams, and the last time he spoke to the Sinn Féin leader was in 2013.
Mr Adams has insisted he received the information from the Stack family, and passed on the details to An Garda Síochána when the case was raised during the general election campaign.
However, the most serious point of contention between them is whether Mr Adams should reveal the identity of the senior IRA figure to the Garda. He has declined to, but Mr Stack has insisted it will assist gardaí in their investigation into the murder.