Loughinisland: while some officers covered for loyalist informants they failed to cover their own tracks
DR Michael Maguire's report which concludes there was collusion between some police officers and loyalist paramilitaries is a game changer.
The document is 160 pages long and every one of those pages is explosive containing details of cover up, complacency and collusion in investigations into loyalist activity, including gun-running.
While asked to probe the Loughinisland attack, which claimed the lives of six men watching a football match in the Heights Bar, Dr Maguire was expected to pick up on where his predecessor Al Hutchinson left off.
Back in 2011 when the former Canadian Mountie delivered his short report finding no evidence of wilful collusion, the families of the victims and those injured in the Loughinisland attack were at first devastated, then angry, then determined to push ahead with their fight for the truth.
Dr Maguire, chose not to follow up on the previous report, instead he started from scratch. More than that he went back to the very beginning, to the source of the weapons used in the attack.
To that end and his investigators have carried out probe that led them to places no establishment figure, no investigator and no ombudsman has dared to go before.
He has uncovered a web of collusion and what he called a "see no evil hear no evil" culture when dealing with informants that will earn him no friends among those in the higher echelons of authority, but has earned him the gratitude of those victims who felt they were screaming into the darkness for 22 years.
This goes further anything that has gone before. Even the probes by Nuala O'Loan into the Omagh bomb and later the activities of the Mount Vernon UVF stopped short of going to the source.
Dr Maguire went back ten years before Loughinisland to the plot to transport a huge shipment of arms into Northern Ireland for use by the UVF, UDA and the shadowy Ulster Resistance.
This shipment arrives in Northern Ireland in the late 80s, with army agent Brian Nelson and police informer Tommy 'Tucker' Lyttle directing the plot. It was stored at the farmhouse of a former RUC reservist James Mitchell who had previously stored guns for the UVF.
Within months the death toll of victims at the hands of loyalist paramilitary groups trebled.
And of 70 victims murdered or injured with the smuggled Browning handguns and VZ58 assault rifles, few have received justice of any kind.
Decent detectives and uniformed officers keen to bring paramilitary killers to justice had their hands tied by Special Branch who refused to pass down vital information. Dr Maguire said they were at times "operating blindfold".
Families' solicitor Niall Murphy - who refused to give up regardless of how many doors were shut in his face - described one officer who tried to investigate the murders but was hampered by Special Branch colleagues as "a good apple in a bad barrel".
There were tears among the victims' relatives yesterday. Tears of sadness for lives needlessly lost, tears of relief that someone finally recognised there was collusion in their loved ones deaths, and tears that years of campaigning had finally produced the answers they had fought so hard for.
The Loughinisland families finally have truth but they don't have justice. Police officers destroyed evidence and missed investigative opportunities. It is unlikely that any of the loyalist killers responsible will ever be brought before the courts.
However, those officers who the ombudsman found had engaged in acts of collusion may yet find themselves under investigation for misfeasance in a public office. They took great steps to cover up allegations of wrongdoing against others, but failed it seems to cover their own tracks.