The terrible tragedy of Thomas Niedermayer and his family is a reminder that there are still two distinct groups of people living on this island – those involved in such barbarity and the vast majority who had nothing to do with it.
Mr Niedermayer, as an RTE documentary revealed at the weekend, was kidnapped, pistol-whipped, murdered and his body buried in a shallow grave.
He was chief executive of the Grundig factory in west Belfast, which employed 1,300 workers in the 1970s. He fell victim to one of his employees, Brian Keenan, then a trade union official, who also happened to be one of the most ruthless leaders of the IRA.
Mr Niedermayer's body was not discovered until eight years after his death. The full extent of his family's suffering is now revealed.
His widow committed suicide, walking into the sea at Greystone in County Wicklow, and his two daughters also took their own lives, in South Africa and Australia.
Keenan went to his grave as a revered republican, mourned and saluted as one of the architects of the peace process. Only now do we learn of the gruesome role he played in Thomas Niedermayer's murder.
It is hard to believe that almost 15 years have elapsed since the signing of the Good Friday Agreement and still such brutal reminders of the past are haunting Northern Ireland.
Hardly a week passes without another revelation about people involved in the dirtiest of dirty wars. Northern Ireland must have more rehabilitated, reformed, even born-again ex-terrorists per head of population than anywhere else in Europe.
Ordinary, decent people, who never fired a shot, or planted a bomb, have swallowed hard and agreed, in the interests of peace, to forgive – if not forget.
The penalties for the most heinous crimes were lifted. Those responsible have walked free from prison, hugged and welcomed back into their family and community folds as if they had done nothing untoward in the first place.
For some at least, their notoriety has not been the undoing of them. Far from it. It has proved a passport to political success, particularly in the case of republicans, if much less so with former loyalist paramilitaries. Unlike the Niedermayer family, life after violence has been much better.
Those who were involved in these terrible events now strut the corridors of power in Ireland, north and south, with a swagger of importance, but still a total reluctance to come clean with the people of this island.
They should not forget that, but for the extraordinary willingness of the law-abiding majority to turn the other cheek and to shake hands which undoubtedly have been stained with the blood of victims such as Thomas Niedermayer, they would not be in the positions of influence they hold today.
They walk our streets, seemingly oblivious to the damage they did to people's lives, but, worse still, regarding themselves as worthy judges of our lives today.
At times, it is as if the past had never happened, so confident are they about the present and the future.
They utter regrets, but show no shame. They distance themselves from the worst savagery, without admitting what part they played in it.
At every turn of this wicked road, the past is sanitised. Excuses are found for the most despicable acts of terror. No one does the blame-game better than those who shoulder more blame than anyone else.
Righteousness is on their side. They accuse everyone but themselves of connivance and cover-up. They fail to admit to the flaws in their own behaviour, but can find plenty of faults to complain about in the lives of others.
Fifteen years on, a little more contrition might be expected, perhaps, even a belated recognition that, in demanding inquiries into the behaviour of others, they had a case to answer themselves. Alas, that is not apparent.
Politics in Northern Ireland means listening to a public representative moralising and pontificating on the rights and wrongs of an issue, or incident, as if that person was totally oblivious to his, or her, own past dishonourable deeds.
Distrust, suspicion and the continued deep divisions in this community are down to many factors. One is the failure of those involved in the terrorism which took Thomas Niedermayer's life and that of so many other innocent bystanders to bare their souls and tell the truth about their pasts.
Such obfuscation is a major reason why Northern Ireland remains such a fragile political experiment in power-sharing.