Glennane Gang case before Court of Appeal
A probe into a bomb linked to a loyalist unit behind more than 100 murders met the "gold standard" of securing a conviction, the Court of Appeal has heard.
As Northern Ireland's Chief Constable challenged an order compelling him to compete an overarching investigation into suspected state collusion in the Glenanne Gang's killing spree throughout the 1970s, senior judges were told human rights obligations have been fulfilled.
Counsel for George Hamilton also stressed the appeal was about ensuring clarity over important points of law.
Tony McGleenan QC said: "We recognise that its vexing for the next of kin of the deceased to be involved in protracted litigation of this type."
Last year the High Court ruled that police unlawfully frustrated any chance of an effective probe into the series of deadly terrorist attacks.
Relatives who lost loved ones were denied in their legitimate expectation that the now-defunct Historical Enquiries Team (HET) would publish a thematic report, a judge held.
The verdict was reached in a legal challenge brought in the name of Edward Barnard.
Mr Barnard's 13-year-old brother Patrick was among four people killed in a St Patrick's Day bombing at the Hillcrest Bar in Dungannon in March, 1976.
Five years later Dungannon UVF member Garnet James Busby was convicted after admitting his role in the no-warning attack.
The murder gang based at a farm in Glenanne, Co Armagh allegedly contained members of the Royal Ulster Constabulary and the Ulster Defence Regiment.
Up to 120 murders in nearly 90 incidents in Mid Ulster and border areas are under scrutiny.
They include the 1975 Miami Showband Massacre, where three members of the popular group were taken from their tour bus and shot dead on a country road in Banbridge, County Down, and the Step Inn pub bombing in Keady a year later, which claimed the lives of two Catholics.
It has also been linked to the murder of 33 people, including a pregnant woman, in the 1974 Dublin and Monaghan bombings.
A draft HET report into alleged security force collaboration with the killers was said to have been 80% finalised before being shelved.
Mr Barnard and other relatives wanted to have police compelled to complete the full investigation and publish the findings.
Counsel for the PSNI had insisted it would be an unnecessary step to force police to finalise an overarching report he claimed had yielded no new investigative opportunities.
But at the conclusion of the High Court case the Chief Constable was ordered to complete and publish an overarching thematic report.
Appealing the verdict, Mr McGleenan claimed it "fell into error" in its analysis of key legal questions, including the application of Article 2 of the European Convention on Human Rights.
Turning to the facts surrounding the Hillcrest Bar bombing, he pointed to the prosecution, conviction and life imprisonment imposed on Busby in 1981.
"The gold standard in terms of the analysis of Article 2 is to ensure a process is in place to allow the identification and prosecution of a perpetrator," he said.
"That gold standard was available in this case, was met and on one analysis discharges the Article 2 obligation."
The appeal continues.