25

It’s in the blood

BLOOD HAS LONG CAPTURED the imagination of man. From William Shakespeare’s Macbeth to Rafael Sabatini’s Captain Blood, our literature has abounded with stories of this crimson fluid. It has been the hallmark of the sinister, the macabre, and the violent. Countless swashbuckling tales of romance and adventure would have been poor insipid documents had it been washed from their pages. Yet in recent years, blood has become the preoccupation of biologists rather than novelists, and the romance has been supplanted by a long, painstaking study of cells and platelets as its arcane mysteries have been increasingly exposed.

The scientific knowledge so accumulated seemed almost impenetrable to me when I picked up the first sheet of paper in a stack a foot high that had been subpoenaed from one of the scientists, and I saw a series of notes in point form, each consisting of words and symbols. It took me twelve hours with a professor of immunochemistry to work out what they meant and to gain some understanding of their potential significance. I then glanced at the balance of the stack, and wearily accepted that this part of the case was going to take some time.

The first scientific witness was Tony Raymond, a senior and experienced forensic biologist attached to the Victorian Forensic Science Laboratory. He had been responsible for much of the independent testing carried out on behalf of the royal commission, and presented a paper entitled ‘What is blood?’ which he proceeded to explain with the aid of an overhead projector. It was a scholarly exposition, lamentably lacking in anything remotely swashbuckling, and it revealed that within each drop lay a microscopic world of unbelievable complexity. Had its intricacies been known to Shakespeare, theatre-goers might have been treated to the spectacle of Lady Macbeth becoming demented at the ‘damned spot’ of the phosphoglucomutase and other polysyllabic proteins clinging to her fingers. Yet it was from these myriads of tiny molecules that the Crown had been able to construct a case every bit as damning as the blood of the slain Duncan.

Whilst the High Court had held that the tests conducted by Mrs Kuhl had failed to prove beyond reasonable doubt that the blood in the Chamberlain’s car had come from an infant, it had nonetheless concluded that it had been open to the jury to infer from other evidence that it had been the blood of Azaria. Now both the Crown and the defence had an opportunity to fight these issues again. The Crown would seek to exclude any reasonable doubt that the blood had contained levels of foetal haemoglobin found only in babies less than three months old. On the other hand, the defence would contend that there was probably no blood in the car at all; or that, if there was, it was limited to a small amount on the hinge of the front passenger’s seat that might have come from some innocent source.

The evidence of blood in the car was crucial. The Crown case was that Azaria had been murdered whilst Lindy sat in the front passenger’s seat. As the child’s throat was cut, an artery was severed, and blood spurted upwards at a trajectory of approximately forty-five degrees, producing the spray pattern found on the plate under the dashboard. More blood dripped downwards, some landing on her tracksuit pants and falling onto the carpet. Whilst one could not see bloodstains in the carpet, the orthotolidene testing had produced a second-stage reaction of vivid peacock-blue, characteristic only of blood. The implication was obvious: the blood had been cleaned up, but the Chamberlains had been unable to completely eradicate it, and telltale trace elements had remained. Blood had also run down the side of the seat and hinge in a manner that could occur only when the seat was occupied, and more had been found on the crossbar and under both the carpet and underfelt beneath the seat. There was blood on a towel and on a pair of scissors that might have been the murder weapon, or that might have been used to cut the jumpsuit later in the evening. As if all this were not enough, Mrs Kuhl’s tests established that the material from the two droplets cut from the spray pattern contained tell-tale levels of foetal haemoglobin — and so did the stains found on and under the seat, on the towel, the camera bag, and probably the scissors. If all these allegations could be confirmed, there could be little doubt that the child had been murdered.

But by the time the royal commission got under way, the first chink had already appeared in this seemingly impressive wall of evidence. The research by Smith had established that the under-dash spray had consisted not of blood, whether infant or otherwise, but of sound-deadening material. That alone was significant; if the tests on that material had been utterly misleading, how could one trust the others? And more revelations were to come.

Sergeant Huggins of the Victorian Police Force had examined the stains on the crossbar under the seat and under the carpet, and concluded that they could not have got there from blood flowing down the side of the seat as the Crown had suggested.

A number of forensic biologists expressed general agreement that the orthotolidene test was merely a screening test. A positive result indicated that the substance might well be blood and that it was worth carrying out further tests to resolve the matter, but it was ‘quite wrong’ to treat a positive reaction as even prima facie evidence that it was blood. At Dr Scott’s direction, another forensic biologist, Dr Craig Fowler, carried out a series of tests to determine whether copper dust would produce a similar reaction, and found the reaction so similar that even an experienced forensic biologist might be deceived. The Chamberlains, of course, had lived in Mount Isa, one of the greatest copper-producing areas in the world.

This was of immediate interest to Boettcher, who promptly headed to Mount Isa and collected samples from thirty-two different areas. The results varied from place to place, with some being ‘extremely strong’, some revealing ‘only specks of blue colour’, and others ‘perfectly negative’. However, sandy material collected from the street where the Chamberlains had lived produced specks of the immediate peacock-blue reaction that Mrs Kuhl and Dr Baxter had insisted were characteristic of blood. Dust taken from the floor on the passenger’s side of a Daihatsu also provided a strong positive reaction, as did dust in a groove of the dashboard light switch. Boettcher observed that Mrs Kuhl’s description of the reactions from the outside of the camera bag — ‘in the seam grooves there were discrete specks that were strongly positive for the orthotolidine test’ — was ‘a good description of the sorts of results that I obtained in literally dozens of tests at Mount Isa’. As Porter pointed out, it was difficult to imagine that the whole district was awash with blood.

The risk of injustice being done due to faulty assumptions that chemicals only react to certain substances had already been graphically demonstrated. Five years before Azaria’s disappearance, the ‘Birmingham Six’ had been convicted in England of having murdered 21 people in a series of pub bombings. Apart from their confessions — apparently made under duress and later discredited — the main evidence against them had been expert evidence suggesting that traces of nitroglycerine had been found on the hands of two of their number, Paddy Hill and Billy Power. Positive results had been obtained from the Greiss test, which was intended to detect the presence of organic nitrate compounds. All six were convicted, and spent 17 years in prison before their convictions were quashed. Amongst other criticisms of the Griess test, it emerged that shuffling an old pack of playing cards could produce a positive result, and that the men had been playing cards almost immediately before they were arrested. Now Fowler and Beottcher had revealed that orthotolidine could be equally misleading.

The suggestion that there were blood spots on the tracksuit pants proved equally dubious. The drycleaner, Mrs Hansell, had thought the spots looked like blood, and they had been removed by a blood solvent she referred to as the ‘green label’, but they had never been scientifically tested. Dr Scott said that a drycleaning operator might easily be confused by drops of fruit juice or other liquids. Even an experienced forensic biologist had difficulty in identifying blood from a visual inspection, especially on a dark background such as the navy-blue portion of the tracksuit pants. Noel Dawson, the laboratory manager of a company that produced similar drycleaning solvents, said that many kinds of stains could be removed by the chemical Mrs Hansell had used. Dr Scott agreed that blood could not be validly detected in this manner. In fact, whilst Mrs Hansell had found that one application of the solvent was normally sufficient to remove bloodstains, the stains on the tracksuit pants had required a further application. Whilst this was scarcely conclusive, it tended to suggest that they had not been blood.

Mrs Kuhl gave evidence, again maintaining that the immunological tests had established the presence of blood from an infant. She received some support from Dr Baxter and Dr Culliford, though Culliford was too ill to come to Australia again, so the Crown was obliged to rely upon the evidence he had given at the trial and on a subsequent report. Nonetheless, the reliability of her conclusions was questioned on a number of grounds.

In the first place, the crossover electrophoresis, or counter-current electrophoresis test, had been an inadequate procedure for proving the presence of foetal haemoglobin. Professor Ouchterlony explained that ‘the usual thing is to run the counter-current electrophoresis as a presumptive test and then, when you’ve got something which seems to be positive, then verify [it] by additional tests ... and that, as far as I understand, has not been done … He explained that the technique had been invented to provide a means of ‘rapid clinical diagnosis’, but that the results needed verification. Professor Leach, Professor Nairn, Professor Boettcher, and even Dr Baudner, who was the research director of Behringwerke, the company that made the antiserum, all agreed that it was ‘not good enough’ to use crossover electrophoresis.

In the second place, it had been inappropriate to use the procedure without undertaking a series of ‘control’ tests to determine the manner in which the particular batch of antiserum would react when used on a range of blood samples. Professors Ouchterlony, Leach, Boettcher, and Nairn, and Dr Lincoln, a forensic biologist from London, all stressed the need for such a regimen of testing. The Crown relied upon the opinion of Culliford’s successor, Dr Peter Martin, but even he agreed that it was ‘undesirable’ not to pretest the antiserum. Dr Baudner stressed the fact that it was merely a research product. It was up to the user to determine that it was reliable in her hands.

In the third place, a number of expert witnesses had found that the antiserum was not monospecific — that is, it would react to other molecules as well as foetal haemoglobin. The evidence was not all one way. Lincoln, Scott, and Martin had all used the antiserum in crossover electrophoresis testing at dilutions of approximately 1:1,000 without obtaining cross-reactions with adult blood. However, techniques and apparatus differ from laboratory to laboratory, and Mrs Kuhl’s demonstration plates provided undeniable evidence of the type of reaction which the antiserum could produce. Nairn maintained that the ‘double banding’ suggested that the antiserum was not monospecific. Boettcher agreed and, whilst Baudner was not prepared to concede this, he said that one would need to find the cause of the double banding before one could rely upon the results. Dr Baxter and Dr Martin both suggested that the double banding might be explained by two groups of foetal haemoglobin molecules that had migrated across the plate at different speeds and had encountered the antiserum at different points. Professor Ouchterlony dismissed this suggestion, explaining that the first reaction would create a barrier that could not be passed by blood molecules of the same kind. It clearly had a second specificity, Ouchterlony said, ‘and that cannot be argued with’.

In the fourth place, it emerged that, so far as any of the experts knew, no one had ever attempted to test denatured blood in an attempt to prove that it had come from an infant. Though she might not have known it at the time, the situation facing Mrs Kuhl had been unique in the history of forensic science. As another biologist, Leo Freney, put it, ‘it was tiger country’. Despite Baudner’s scepticism about the antiserum having more than one specificity, he agreed with Boettcher that one could not rely upon its reaction with a denatured blood sample.

It fell to Professor Nairn and Professor Leach to explain the nature of the problem. The antiserum had been made by taking cord blood — blood from the umbilical cord of a newborn baby — and injecting it into a rabbit. The rabbit’s immune system would then go to work, busily manufacturing antibodies to the foetal haemoglobin molecules. But cord blood contains about 30 per cent adult haemoglobin, which had to be removed before it could be injected into the rabbit, and this was done by subjecting the blood to a centrifuge and exposing it to adult haemoglobin antibodies. This could never be done with complete accuracy, and some antibodies to residual quantities of adult haemoglobin could also be produced. Furthermore, the process inevitably caused some molecules to become denatured and to expose different ‘antigenic determinants’. The rabbit’s immune system would then manufacture not only antibodies to foetal haemoglobin, but also antibodies to the denatured molecules. The antiserum so obtained could later react with denatured blood, even if it did not contain foetal haemoglobin. And this would not be picked up by control tests, because they relied on samples of fresh blood containing no denatured molecules.

Denaturation occurs naturally with the passage of time, but it is accelerated by heat — and the Chamberlains’ car had been exposed to extreme heat at Uluru and Mount Isa before being examined some thirteen months after Azaria’s disappearance.

The suggestion that the the presence of foetal haemoglobin in the car had been confirmed by a band on a haptoglobin plate also proved untenable. Dr Baxter conceded that one had to be very cautious before drawing such a conclusion and that there were ample grounds for this warning. Both Raymond and Scott said that one would not normally expect to find haemoglobin bands when the sample was at least thirteen months old, and Baxter had carried out tests which showed that, under extreme circumstances, they could disappear after fifteen days. Boettcher and Raymond reported obtaining double bands from adult blood, and Boettcher produced a sample plate demonstrating this phenomenon. Mrs Kuhl conceded that she had used no ‘foetal control’ on the haptoglobin plate — a precaution that Scott regarded as indispensable — and they seemed to be the wrong colour. Baxter agreed that it would have been surprising to have obtained reddish-brown bands from blood of that age. Furthermore, he estimated that the band in the ‘foetal position’ contained at least 50 per cent of the total haemoglobin, double that which Scott had estimated was contained in the blood on Azaria’s jumpsuit. This suggested that, if the band was really foetal haemoglobin, the blood had not come from Azaria, but from an even younger baby.

In the light of these difficulties, it was difficult to accept that the tests offered any valid evidence of infant blood in the car. After the relevant issues had been canvassed with him in cross-examination, even Baxter ultimately said that he could not say either ‘yes’ or ‘no’, and that ‘at this stage’ his position was ‘ambivalent’.

The real question seemed to be whether there had been any blood in the car at all. Raymond had carried out an extensive program of tests, but had detected blood only in a nasal secretion on the back of a seat. As he readily conceded, it was difficult to imagine that Mrs Kuhl could have ‘got it so wrong’. But he, Scott, Baxter, Boettcher, and Nairn all said that if there had been significant quantities of blood present in 1981, they would have expected the tests subsequently carried out in 1986 to have still detected it. Raymond and Baxter were at pains to point out that some of it may have been removed by the testing in 1981, and that it was conceivable that further denaturation had accounted for the lack of any reaction in 1986. Nonetheless, it was ‘surprising’ that no blood was found, even on the hinge.

Dr Cornell said that the PGM test might also have been inaccurate due to the denaturation of the material tested. Freney agreed. A partly denatured stain could give misleading results. Others were surprised that Mrs Kuhl had obtained any PGM results. Baxter had seen some stains that were 18–24 months old, but agreed that this was quite exceptional, Raymond, Martin, and Professor Renate Meier had found eight months to be about the limit, and Scott and Boettcher agreed that reliable results could not be expected from a denatured stain that was 13 months old.

Cornell also said that when he had tested the carpets of the car in 1982, he had been unable to find any trace of the hundred or more proteins found in blood.

Further evidence that the orthotolidine reactions might have been attributable to copper dust, rather than blood, was provided by the results from another screening technique known as the Kastle-Meyer test. It is somewhat less sensitive than the orthotolidine technique, but has been used to detect bloodstains up to 20 years old. It also produces fewer ‘false positives’ than orthotolidine. Mrs Kuhl had used both techniques, and had obtained negative results from the Kastle-Meyer test.

The Crown made some attempt to defuse the revelation that the spray pattern of the plate under the dashboard was actually sound-deadening material by arguing that foetal blood might have splashed onto the two drops that Mrs Kuhl had tested. But Raymond had established that there was no blood of any kind remaining on the plate, and Morling was quick to point out that it would have required an amazing coincidence for foetal blood to have struck the plate in such a manner that only the surface of the two droplets were touched and for Dr Jones to have chosen those droplets as representative samples. Furthermore, when Mrs Kuhl tested the spray pattern with orthotolidine, the result had been negative.

Even Martin, upon whom the Crown relied heavily, conceded that if there had been any blood in the car when Mrs Kuhl tested it, the quantities must have been ‘very small’. Boettcher and Nairn agreed but, perhaps ironically, it was left to another of the scientists who had been called at the Crown’s request to administer the coup de grace to this aspect of the case.

Professor Ferris was an eminent forensic pathologist and president of the International Society of Forensic Scientists who brought to the inquiry extensive experience in investigating deaths due to accident or crimes of violence. He explained that if the child had been killed in the car as the Crown suggested, there would have been ‘visible and readily detectable amounts of blood present in the car almost in spite of whatever means was used to conceal it’. Yet the evidence was plain. None had been seen on the night in question by the Demaines, Bobbie Downs, or anyone else. None had been detected by Senior Constable Graham when he conducted a minute search of the car some six weeks later. Cornell had been unable to find any protein when he tested the carpets in 1982. And Raymond had not been able to detect any residual traces of blood in the car, though no less than seven scientists had agreed that some positive reactions would still have been expected had any substantial quantities been in the vehicle when Mrs Kuhl examined it. All this seemed to point to the one conclusion. There had been no blood in the car — other than, perhaps, minute quantities of the kind which Martin said one might expect to find in any family car.

The Crown’s claim that Azaria had been murdered in the car had been effectively demolished.