Lindy and Michael Chamberlain

Lindy Chamberlain was 64 yesterday (Sunday 4 March 2012). She has spent half her life fighting the accusation that she murdered her baby daughter Azaria at Ayers Rock in 1980.

She is continuing the fight now. She is wants the Darwin coroner to find that Azaria was killed by a dingo and for her death certificate to reflect this.

I covered the Chamberlains' appeals in the Federal and High Courts in 1983 and 1984. That and subsequent events have been an instructive experience.

At the end of the Federal Court appeal I was convinced of Lindy Chamberlain's guilt. Ian Barker QC, for the Crown, put an incisive case, as he did at the trial.

In the Federal Court Barker was there to argue that the jury's guilty verdict was safe and satisfactory.

He used the rope analogy. Each strand of evidence, he said, was not in itself convincing, just suggestive of guilt. But taken together they formed a strong rope.

He cited the foetal blood in the Chamberlain's car; the infrared image of a hand on the jump suit (which had been found a week later); blood splatter evidence; vegetation; sand grains only on the surface of the blood drops; evidence of dingo jaw width; scissor-like slicing of the fabric of the jump suit and so on.

It was like an early version of CI. Very convincing when taken together.

It convinced the Darwin jury, especially when another ingredient was added.

Barker told the jury that Territorians knew that crocodiles were dangerous and could take a baby or an adult, but that dingoes just did not do that. Territorians knew that.

It was the frontier mentality. Lindy's lawyer was from Melbourne – down south where they don't understand these things. And the jury bought it.

They bought it despite the judge, Justice James Muirhead, summing up in a way that a sophisticated jury would suggest an acquittal was warranted.

I have it on unreliable hearsay evidence (but I can get no better) that Muirhead was aghast at the guilty verdict and rang a judicial colleague to say so.

The Chamberlain case is yet another example of the defects of the jury system. Juries do not have to give reasons for their decisions. They are required to act in haste – they are virtually locked in a room until they come to a verdict. They act anonymously. They are selected at random with no testing of their capacity to make decisions.

Worse, once they decide, the appellate system gives far too much weight and respect to their verdict. Appeal judges are not allowed in law to substitute their own conclusions for the jury's. They can only overturn a jury verdict if it is shown to be unsafe, unsatisfactory or dangerous.

It is a damn silly process because juries give no reasons. We can never know whether in this case or any other a jury gave weight to irrelevant matters: "We know as Territorians that dingoes do not take babies or attack humans." "She belongs to that weird religion."

That said, it is hard to blame the jury in the Chamberlain case for getting it wrong because of the way the case was put to them. They were invited to conclude that when you exclude the impossible (that the seven or eight pieces of scientific evidence were wrong) you have to conclude the improbable (that a mother without any motive killed her child and somehow disposed of the body).

In the words of Chief Justice Harry Gibbs and Justice Anthony Mason in the High Court, "The jury should decide whether they accept the evidence of a particular fact, not by considering the evidence directly relating to that fact in isolation, but in the light of the whole evidence, and that they can draw an inference of guilt from a combination of facts, none of which viewed alone would support that inference."

That reasoning invites the acceptance of individually shaky bits of evidence because overall they point to a conclusion of guilt. Worse, a jury bombarded with scientific evidence could fall for the trap of circular logic by allowing a hunch or gut feeling of guilt to emerge and then reassuring themselves that the scientific evidence supports it.

It is the Barker rope trick. It is still good law.

It might be fine when the evidence is a combination of ordinary circumstantial evidence, but not if it is scientific evidence. Science is science, not conjecture. The science should be convincing or should be excluded from the jury.

People chosen at random are not likely to be equipped to cope with contentious scientific evidence.

In the Chamberlain case, the reverence that six of the eight appeal judges (three in the Federal Court and three of the five in the High Court) had for the jury verdict – respect for the good sense of common person's view of the world – led them astray.

The jury did not apply good sense – why would a mother on holiday kill her baby and having done so concocted a story about a dingo taking her baby? The judges should have applied good sense, but couldn't because of the state of the law and because they had no idea how the jury came to its verdict.

We now know the science was dud and we know a lot more about dingoes – there have been a lot more attacks since then, at least one of them fatal.

Indeed, research by the University of Western Sydney suggests that dingoes in Australia are behaving like any wild animals disturbed by encroachment of human populations.

Dingoes prefer a diet of small native animals within a fairly well-defined and learnt territory. Dingoes teach their young the limits of their territory and the tricks of catching and killing native prey and the dangers of moving out of their territory. If you disrupt that pattern by killing or trapping adult dingoes or by leaving human waste food around you invite dingoes to go for stock or small humans as easy prey.

Lindy Chamberlain has consistently said a dingo took her baby. She always said Azaria was wearing a matinee jacket. The jacket was ultimately found near a dingoes' den during the search for the body of a tourist who fell from Ayer Rock. That led to an inquiry and the quashing of the convictions. But still the death certificate remains a falsehood.

No fair person could possibly conclude anything else now but that a dingo killed Azaria Chamberlain and that Lindy Creighton Chamberlain and Michael Chamberlain are entitled to have the death certificate reflect that.