New forensic evidence has been uncovered by detectives investigating more than 50 murders linked to the notorious IRA agent Stakeknife.
More suspects are being brought in for questioning – members of both the security forces and the Provisional IRA – as part of Operation Kenova.
The probe is centred on possible crimes by paramilitaries, agents and Army and police handlers linked to Stakeknife, allegedly the military’s highest-ranking spy within the IRA.
Multiple murders, attempted murders, torture and unlawful imprisonments are included.
The senior officer in charge of the independent police probe, Bedfordshire Police Chief Constable Jon Boutcher, says the operation is not a witch-hunt against the security forces.
“It is not a re-writing of history, but it is an authentic search for the truth,” he said.
“It is an investigation that will pull no punches, taking place for the families who have never had an investigation.”
The high-ranking mole Stakeknife reputedly led the IRA’s “nutting squad”, which brutally interrogated and murdered suspected spies and informers during the Northern Ireland conflict.
In 2003, Stakeknife was widely named as west Belfast man Freddie Scappaticci, but he has always strongly denied the allegation.
According to Mr Boutcher, witnesses have told how records were removed or invented by members of the security forces as part of the wealth of new information unearthed.
New DNA profiles and suspect fingerprints have also been uncovered by detectives, using ground-breaking techniques to review and uncover forensic evidence which was not previously available.
They are due to present files to prosecutors next year in a bid to secure convictions.
“Now I think, time will tell, it is the right time for an investigation like this because of the development of the forensic opportunity that we have got,” Mr Boutcher said.
“Although these investigations are difficult the longer ago that something occurred, they are not impossible - it is not out of reach to find the truth.
“As long as that is done in a fair and even-handed way to everybody, there should be no concerns from the security forces, the paramilitaries, political parties, Government, about an investigation - because it is what everybody with any decency should advocate for and want.”
- UTV Investigations Correspondent Sharon O'Neill reports: