The family of a Catholic man whose murder was found to involve collusive behaviour has voiced their "dismay and hurt" after a request for a new inquest was rejected.
The family of Patsy Kelly had called for a new inquest after a damning Police Ombudsman report was published last month.
Read More: Former DUP man suspected of Patsy Kelly murder link within hours
A member of Omagh District Council, Mr Kelly is thought to have been killed as he returned home from work at a bar in Trillick, Co Tyrone, in July 1974.
His remains were weighed down before being dumped in Lough Eyes in Co Fermanagh and were recovered three weeks later when they floated to the surface.
It was later found he had been shot six times.
The Kelly family, and many in the local community, have long suspected the involvement of UDR members in the murder.
While no-one has been convicted, several former members of the UDR have been arrested and questioned.
Ex-DUP assembly member and UDR man Oliver Gibson was under suspicion of involvement within hours of the killing almost 50 years ago but was never charged.
He died in 2018, aged 83.
In a hard hitting report, Police Ombudsman Marie Anderson said there was a series of "significant" investigative failings in the case.
These included a failure to verify UDR alibies, forensic failings, ‘latent’ investigative bias and no dissemination of intelligence.
She revealed that RUC Special Branch and a senior officer in the area were aware of “significant intelligence” that a UVF unit was active in Fermanagh at the time of Mr Kelly’s murder.
A number of this unit’s members were “either directly linked to Mr Kelly’s murder and other terrorist attacks”.
The ombudsman also revealed that a number of security force members, including police officers, “were also linked to this unit and its activities”.
In the letter, an official at the attorney general's office said it was the fourth time an inquest request had been made.
"The attorney has read the Police Ombudsman's statement and it is clear that the complaints raised by your client have been thoroughly investigated by her," the official wrote.
"The attorney considers it unlikely that a new inquest would add materially to what is contained in the police ombudsman's statement.
"In all the circumstances the attorney does not consider that it would be advisable for her to direct an inquest at this time."
In a statement the Kelly family said it was "with great dismay and anger that we were informed of the attorney general's decision to refuse a fresh inquest" into the murder.
"This decision has caused an enormous deal of hurt to our family," the statement added.
The Kelly family now intend to apply for a judicial review.
"The recent publication of the (police ombudsman) report into Patsy's murder has highlighted the depth and scale of collusion in a case that has spanned across police, loyalist paramilitaries and British military forces," they say.
"However, the PONI investigation only had the remit to investigate police misconduct.
"The granting of a fresh inquest, bearing in mind the original inquest of 1975 was effectively incomplete, would allow the spotlight to focus on UDR involvement in tandem with a then active UVF unit in Fermanagh and would possess the power to compel witnesses to attend and to submit testimonies."
The family added that given what is known "in regard to the wide scale collusion across multiple agencies of the British state, it is simply appalling and incomprehendable that a fresh inquest has been denied".
Solicitor Adrian O'Kane, of Patrick Fahy and Co Solicitors, said "the suggestion that the Kelly family obtained all the relevant answers from the PONI report is both wrong and misconceived".
"The Police Ombudsman, by definition, is confined to examination of issues relating to the conduct of the RUC/PSNI," he said.
"The Kelly family have always contended that all of the other components of the state - including Ministry of Defence and the security services - have important issues to address and questions to answer resulting from the death of Patsy Kelly.
"These can only be properly and fully addressed in a fresh Inquest."
