A public inquiry into the Barron report on the 1976 murder of Co Louth man Séamus Ludlow will begin today at an Oireachtas sub-committee.
A report by Mr Justice Henry Barron, which was released in November, sharply criticised the Garda investigation into Mr Ludlow's death.
The RUC told the Garda in 1979 that it believed four named loyalists were involved in his killing, but this information was not pursued by the Garda.
No one has ever been charged with the murder of Mr Ludlow (47), a single man. He was shot dead on May 2nd, 1976, as he went home from a night out.
The Barron report said the Catholic man had no connections with any subversive organisation.
In Mr Justice Barron's report, he was described by family, friends and colleagues as "a quiet, unassuming man whose life revolved around work and home". He was known for charitable work, and had acted as Santa Claus in a Dundalk housing estate for many years.
Mr Ludlow had worked as a labourer for various employers. At the time of his death he was employed in a local sawmill.
The RUC told the Garda in 1979 that it believed that Paul Hosking, William Long, Séamus Carroll, and a then UDR corporal, James Reid Fitzsimmons, were involved in the murder. However, they were never questioned in Northern Ireland by the Garda.
The Barron inquiry concluded that senior Garda officers feared they would have to allow the RUC the right to interview suspects in the Republic in return.
The Barron inquiry carries full Dáil privilege because it was published by the Oireachtas Committee on Justice, Equality, Defence and Women's Rights, chaired by Fianna Fáil TD Seán Ardagh.
The sub-committee will hold public hearings into the report and interview as many key witnesses as possible but will not be able to compel them to attend.
The hearings will be held over six days spread out over the next few weeks up to February 16th.