The families of the victims of the Omagh bombing have told the press this week they plan to take legal action against the British and Irish governments if they refuse to hold a full cross-border independent inquiry into the 1998 attack.
Described by many as the single worst terrorist atrocity of the Troubles, the specially commissioned report by the families claims there were significant intelligence failures on both sides of the border in the lead up to and in the aftermath of the bomb, which claimed 29 lives.
According to RTE, the families reportedly handed the report to the British and Irish governments last June, but they say they have yet to receive a substantive response.
Michael Gallagher, whose 21 year old mechanic son Aidan died in the bombing, told the press the lack of answers from the governments was 'prolonging the agony of the families.'
Meanwhile rights watchdog Amnesty International have reportedly joined the families in calling for a full, independent cross-border investigation into the bombing.
Amnesty's Northern Ireland program director Patrick Corrigan told the press the families who were bereaved or had relations injured by the bomb are still left wondering if it could have been prevented.
'The families have had to suffer the indignity of being drip-fed information over the years, with new wounds opened each time and with none of the bombers ever being held criminally responsible,' Corrigan told the press.
'It is doubly sad that the bereaved families and those injured have now had to commission their own report as a result of the many partial investigations, each one of which opens up new questions.'
Corrigan added that questions remain about alleged state failures in the lead-up to and the aftermath of the bomb. In particular he said there are unanswered questions concerning the gathering and sharing of intelligence material between domestic and international agencies, including the RUC, MI5, the FBI and the Irish Police Force.
Next week marks the 15th anniversary of the bombing which means that pressure on the British and Irish governments to agree to a cross border inquiry are likely to intensify.
To date the families have been unimpressed by the stance taken by Irish Prime Minister Enda Kenny and Minister for Justice Alan Shatter on their campaign.
A spokeswoman for the Irish Department of Justice told RTE that Minister Shatter is still considering the report, presented to him by the group in July 2012.
Former Northern Ireland police ombudsman Dame Nuala O'Loan, who carried out her own investigation into the bombing while in office, was joined by former Metropolitan Police assistant commissioner and counter terrorism chief Bob Quick in the call for an inquiry. O'Loan said what had emerged in the 15 years since the attack was 'cause for enormous concern.'
Several men have faced charges in connection with the terror attack, but no one has ever been convicted of the murders.
Why Martin McGuinness will be remembered for hundreds of years to come