Few of us in the media who covered the Malcolm McArthur story all of 20 years ago now can have forgotten that quite extraordinary saga. During those warm weeks in 1982, as July turned into August, the story unfolded like some gothic horror tale.

Before it was complete it seemed to feature characters straight from central casting as the crazed Anglo-Irish Meath man-about-town succeeded in sucking in not only the attorney general of but even, it seems, taoiseach Charles Haughey himself.

It gave rise to Haughey's famous GUBU (`grotesque, unbelievable, bizarre and unprecedented') remark that forever after seemed to blight Haughey's successive acts and administrations like a mummy's curse. As the central narrative emerged in all its byzantine coils it was easy to forget that at the heart of these events were two tragic young victims, nurse Bridie Gargan and farmer Donal Dunne, who were murdered without mercy.

My particular memory was of being among the small press corps who covered McArthur's charging at Dun Laoghaire court that Saturday morning all those years ago. It was a special sitting, and we were the only people present. Outside, a huge crowd had built up, and as we sat in the empty courtroom we could hear the roars and jeers as, presumably, McArthur was being led in. A succession of doors banged and crashed, and we turned in our seats to see three men in suits suddenly enter the court.

Two were detectives; the one in the middle looked like an extra from an Evelyn Waugh novel. It was Malcolm McArthur in twill sports jacket and trousers. With both hands foppishly buried in his jacket pockets, he contemplated us with a haughty look, cast a critical eye over the condition of the old courthouse and then walked with elegant disdain to his seat right in front of us. If anything, this was a salon entrance, an example of practised and purposeful body language.

In the minutes before the district justice appeared for the hearing, we all sat in a strange, awkward and reverent silence in the dank room, broken only by McArthur chatting away to his detective escorts. As we strained to listen, we were soon astonished to discover that he was actually discussing their star signs with them.

Oblivious of his astounded audience, Malcolm McArthur was busy giving them the full benefit of his small-print knowledge of Sagittarians and Aquarians. With commendable calm and concerned patience, the two burly detectives joined him in this bizarre conversation.

McArthur had just spent the previous four hours with these grave-looking men in crumpled suits, carefully and comprehensively dictating his life story as confession, and presumably by now this strange little relationship was slowly drifting into deep waters uncharted in all of their experiences. Indeed, were it not for McArthur's chalky white face and the tiny tremors I could see coming up the back of his neck and exploding into his jaws, we might for that moment have been just a bunch of ordinary people wearily waiting in a some dentist's or doctor's grotty waiting room.

Afterwards, as McArthur was driven away through the now even bigger howling mob, the overriding emotion of the same detectives was one of relief that they had caught him in time. On the street outside, one of them said to me: "Christ, can you imagine if that insane fucker had turned up one morning in the bank over there with that shotgun loaded?"

I know neither hacks nor policemen are professional shrinks, but the overwhelming impression of all those closest to those events all those years ago was that Malcolm McArthur had taken leave of his senses.

In the years since, no adequate explanation has ever emerged to explain why one so clearly adrift of the classic criminologist's socioeconomic homicidal grouping should have behaved as he did.

This subject formed part of the hinterland of John Banville's remarkable novel about the case, The Book of Evidence. This novel is a deft exploration of the hidden crossing-points in the mind between ego, self-pity, cruelty and naivety.

Now, with the prospect of release on licence looming up, McArthur's strange ghost emerges out of the unforgettable events of that warm summer 20 years ago. Predictably, the tabloids are warning that "he could kill again", and perfectly understandably too, the families of the victims are deeply traumatised.

It is important to assert in these circumstances that the McArthur case now is, by virtue of his imprisonment, essentially a subject for both our society and our penal system as a whole. The notion that somehow he will be set `free' is absurd. A double murderer, currently serving the second longest ever life term in our prisons, neither legally or in conscience can ever be `free'.

What is currently at issue is simply where and under what circumstances he will continue to serve his life sentence. I suspect that if you ask anyone sentenced to life for murder, particularly of McArthur's dimensions, whether serving out their natural life in enclosed, open or even hostel accommodation until death, makes much difference, you might get a dusty answer. Lifers serve time in their heads, not in their cells.

Can you imagine, for example, the crisis that would be created within our penal system if lifers were never to have hope of changed circumstances? Would our prisons be manageable, would the suicide rate not be even worse than it is?

Equally fatuous is the idea that for those contemplating murder, knowing that somewhere at the end of long years in prison a door will open into a different experience would lessen the deterrent value of a life sentence.

One long-term lifer, a woman in fact, told me once that she never met a lifer in her time in prison who didn't approve of capital punishment. Her response was overtly subjective, but she said it with such blackness that I have never forgotten it.

Is it not still important to assert human quality, as opposed to human failure -- and in this, is our society not the better for offering some minimal degree of redemption to one who showed remarkably none to his unfortunate victims all those years ago?

Just as any of our children could have been Bridie Gargan or Donal Dunne, so too some of our children could be Malcolm McArthur.