It is a comforting notion that suffering brings people together - that, however we may bicker and squabble in ordinary times, when things are truly tough we will all pull in the same direction. In cases of violent death, and in particular the death of a child or young person, it is often a hollow fiction. No one understands this better than Jane Steare and Tim Blackman, the parents of Lucie Blackman.

In the eight years since Ms Blackman disappeared, to be found seven months later hacked to pieces and buried in a cave, two parallel human stories have acted themselves out. One is the trial of Joji Obara, convicted yesterday of abducting, dismembering and burying her, although acquitted of actually killing her. The other drama has been that of the Blackman family and the painfully public struggles between the parents.

In the course of researching a book about Lucie Blackman and the Joji Obara case I have got to know all the members of the Blackman family. I like and admire all of them. I can see the points of view of Mrs Steare and Mr Blackman; I have long ago given up trying to judge who is right or wrong.

Those struggles have brought anguish to both sides; once, they very nearly cost the life of Lucie's younger sister. They are a reminder that the victims of a man such as Obara are not limited to those he has raped or killed. Violence sends out waves of heartbreak that topple people far removed from the original offence.

Mrs Steare and Mr Blackman separated in 1995 and divorced bitterly three years later. Mrs Steare says that he had affairs; he admits them but says that they were a consequence of deeper unhappiness in the marriage and that however much fault lies with him, not all of it does.

She - by her own admission a sometimes overprotective mother - begged Lucie, 21, not to go to Tokyo, convinced that something awful would happen to her. Her father, who was living with his wife and her children in the Isle of Wight, was more relaxed but had not been told that Lucie would be working as a hostess.

When the news came two months later that she had gone missing, Mrs Steare telephoned Mr Blackman from her home in Sevenoaks for what was their first conversation in years. She says that he was cold and unconcerned about the fate of Lucie; he claims that she was foul-mouthed and hysterical. It was another of those incidents from a bad marriage that no outsider can ever adjudicate.

Within a week, however, he was in Japan, orchestrating a campaign of media interviews and private investigations to draw attention to the case and put pressure on the Japanese police to find Lucie. Mrs Steare, paralysed by despair at the realisation of her worst fears, first shunned the press and remained at the former family home in Sevenoaks with her son Rupert, 16.

After the arrest of Obara and the discovery of Lucie's body, the pain and recrimination intensified.

Sophie, the sister of Lucie, pleaded with her mother to be allowed to keep some of her ashes; Mrs Steare refused. The night after the burial of the ashes Sophie took an overdose of sleeping pills. Three years later, including several months of psychiatric treatment, she is leading a happy and independent life.

The greatest conflict of all, however, has been over money. For several years, despite insisting that he was innocent, lawyers and agents of Obara have been offering what he calls “condolence money” to the victims of his crimes. All eight of the women he raped have accepted it and despite first saying that they would not accept it, so too have the family of Carita Ridgway, the Australian woman whom he drugged, raped and killed in 1992. Only one person has held out - Mrs Steare.

Since her ex-husband Mr Blackman accepted 100 million yen (at the time about £450,000) in 2006, her anger has been implacable. “As far as I am concerned, Tim accepted 100 million pieces of silver,” she told one newspaper. “Judas was content with just 30.” She asked Hampshire police to investigate Mr Blackman for fraud for accepting this money and she gave her support to a former employee of Mr Blackman's charity, the Lucie Blackman Trust, who alleged financial misconduct against it.

Neither of these investigations has led to any charge. And yesterday one thing, at least, was settled: the trial judge said explicitly that the acceptance of the money by family members had made no difference to the life sentence which he imposed on Obara.

I hope that I never have to experience a loss like that of the Blackmans. And if I did, I do not know how I would react. Perhaps I would grieve like Mrs Steare; perhaps I would be all action like Mr Blackman. I might reject any financial compensation; or I might regard it as the very least that I was entitled to.

None of us have a right to judge those who have been unlucky enough to suffer such a torment.

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