Southern authorities have declined to comment on a case in which the IRA justified a murder in Castlederg by producing a Garda intelligence file about their victim.
Ian Sproule, 24, was gunned down by three IRA men as he drove his car into the garage at his family home in Castlederg in 1991.
Shortly afterwards, the IRA justified the murder by showing a Garda intelligence file, which claimed their victim was a UVF member, to a Londonderry newspaper.
The Sproule family believe that a Garda leak caused Ian to be murdered by the IRA.
In 2012 there were angry exchanges at the Smithwick Inquiry into Garda collusion in Dublin when a senior Garda officer only admitted the existence of an internal investigation into leaks to the IRA under close questioning.
Ian’s brother John said: “Both the UVF and our family have always denied that Ian was in the UVF.
“Our cousin had a farm in Donegal and Ian often drove a tractor to and from it. If the Garda were so convinced he was such a danger why did they never once arrest him for questioning?
“We were so angered when Irish Justice Minister Charlie Flanagan came to Northern Ireland in recent times and demanded an inquiry into the murder of Pat Finucane. We’d been trying to get a meeting with him for some time when he did that. The Finucane family are entitled to truth and justice, but so are we.”
The Sproule family have pressed for years to meet the Garda Commissioner and Irish Justice Minister, but no representative of the Irish government has ever agreed to meet them, he said.
The Garda and Irish Department of Justice failed to respond to his comments.
Ken Funston, advocacy manager with the South East Fermanagh Foundation, says he and the Sproule family met the Garda Ombudsman chairperson and other officials two years ago about the case.
“They told us there were merits in the case and that they would advise us by November 2018 whether they would take it on,” he said. “However they never got back and we have had no reply to the 26 emails sent since then, aside from basic acknowledgements.”
The Garda Ombudsman declined to offer any response to his comments.
Mr Funston added: “Last Friday Ian’s brother and I delivered an expansive file to the Attorney General’s office in Belfast requesting a new inquest. The case merits one in many aspects.”
Dublin recently passed legislation to allow Garda to give evidence in NI inquests, he noted.
“The involvement of Gardai in any new inquest is essential,” he added.
Gregory Campbell MP said he raised the question of Garda-IRA collusion in 1991. Such collusion, he noted, was later confirmed by the Smithwick Inquiry into the murders of RUC officers Harry Breen and Bob Buchanan. “As there is new legislation in the Republic allowing Gardai to give evidence in Northern Ireland, I now support calls for a new inquest into the murder of Ian Sproule,” he added.