Northern Ireland police documents about an IRA bombing that killed 12 people at La Mon House Hotel have disappeared, victims' relatives claimed today.
The hotel, located outside Belfast, was targeted in one of the most horrific attacks of the Troubles, with many of those killed in February 1978 burned beyond recognition by a fireball.
Interviews with IRA men, original papers from up to 100 detectives and notes about a warning call and a car used by the bombers have not been recovered by independent investigators reviewing the case, families said.
They have now renewed calls for a full public inquiry into the bombing.
In a statement today, they claimed: "It would appear to the victims that key documents were removed from the files with the view to protecting IRA members who today may be involved in the peace process at the highest level.
"This case, in common with other major investigations, appears to show that the will to uncover the truth has been curtailed for fear of destabilising the current political process."
The victims, all Protestants, had been attending the annual dinner dance of the Irish Collie Club, and included three married couples.
Most of the dead were seated close to the restaurant window where the device was placed.
West Belfast man Robert Murphy was sentenced to life imprisonment for manslaughter in 1981. He was released in 1995 and died in 2006. A second man was acquitted.
A waitress told a coroner's court inquest: "People were on fire, actually burning alive. I watched men pulling long curtains off the rails and wrapping people up in them to try to put out the flames. I could smell the burning flesh."
The call for an new inquiry followed a review of the police investigation by the independent Historical Enquiries Team (HET) which delivered a report to the families.
On the 34th anniversary of the attack, relatives said they had been left scarred physically and emotionally.
"It is most disturbing that the investigation of an attack described by the RUC as horrific and indiscriminate mass murder has been hampered because key documentation has been mislaid," they said.
Their statement added: "Considering the circumstances of this horrendous crime and the certainty of the involvement of the IRA, the victims are appalled by the absence of diligence shown by the Royal Ulster Constabulary/Police Service of Northern Ireland in ensuring the preservation of all information related to this investigation and also calls into question the integrity and thoroughness of the whole historical inquiry process."
According to the families, the HET did not explain the disappearance of major incident documentation used by the RUC. Nor has there been any attempt to show why original material, recorded by up to 100 investigating detectives following the atrocity, including details of interviews with IRA men, was missing.
They asked Northern Ireland Secretary Owen Paterson to establish a public inquiry, claiming the 81-page HET report revealed nothing new except forensic details about the incendiary device.
Adhesive tape recovered from the bomb was investigated but not enough DNA was found to create a profile, a campaign group working with the families said.
An alarm clock used to trigger the bomb had been modified to allow a maximum delay of 58 minutes. Two fingerprints and two palmprints found in the Fiat car used to transfer the device remain unidentified.
The names of 69 people were mentioned in intelligence documents or featured during the initial investigation but the HET did not know who authorised or sanctioned the attack, according to Ulster Human Rights Watch lobbyists.
A total of 35 people were arrested but the campaigners said that, without original documentation, the details of the interviews are unknown, adding that records were not automatically updated.
Ulster Human Rights Watch said: "It would therefore appear that not all lines of inquiry were reviewed by the HET, but only the main ones, since it is admitted that the review was carried out using prosecution papers only."