Ludlow, 47, a forestry worker from Thistle Cross near Dundalk, was abducted by loyalists as he thumbed a lift home from the Lisdoo Arms in May 1976. He was shot dead and his body was dumped.

One of Ludlow's killers is believed to have been a British military or RUC Special Branch agent. No-one has ever been charged with the murder. The family alleges that there was a "cross-border cover-up".

Family members and senior gardai, possibly including former garda commissioner Larry Wren, will be among those giving evidence to the Joint Committee on Justice, Equality, Defence and Women's Rights which will report to the Dail.

One witness will be a west Belfast man who contacted the Sunday Tribune two months ago about the case. It was believed that gardai didn't travel north to question four loyalist suspects because they didn't want the same rights reciprocated to the RUC.

However, Pat Livingstone told the Sunday Tribune he was questioned by RUC officers in Dundalk garda station in 1975.

"I'm delighted to be able to go before this committee and give my evidence, which I hope will help the Ludlows get justice, " Livingstone said.

The committee hearing centres on the report into Ludlow's murder compiled by former Supreme Court judge Mr Justice Henry Barron.

Ludlow's nephew, Jimmy Sharkey, said: "After 30 years, we might be getting somewhere. It's been very hard for Seamus's brother and three sisters who are all in their 70s.

"We hope the gardai involved won't be reluctant to give evidence. A public inquiry is needed because of the unanswered questions.

Seamus's clothing, two of the fatal bullets, and a record of fingerprints found on chip bags at the scene remain missing."