Former Garda Commissioner Larry Wren has been speaking to the Oireachtas Justice Sub-Committee about the report of the Barron inquiry into the murder of Seamus Ludlow.
Mr Wren says he does not accept the conclusion in the report.
He was expected to challenge the assertion in the report that it was 'most probable' that the decision not to interview four loyalists suspected to be responsible for the murder of Mr Ludlow was made by him.
Mr Ludlow, a 47-year-old single man from Dundalk, was shot dead as he walked home from a pub on 2 May 1976.
Former Detective Superintendent John Courtney finished answering questions at the Justice Sub-Committee earlier.
He repeated his claim, outlined in the report, that Detective Sergeant Dan Boyle told him in 1979 that former Garda Commissioner Wren had advised that no further action was to be taken in the case.
Superintendent Courtney had wanted to interview four named loyalists in Northern Ireland who the RUC suspected were responsible for Mr Ludlow's murder.
The Barron Report on the murder sharply criticised the garda investigation into his death.
The report also concluded that Mr Ludlow had nothing to connect him with any subversive organisations.