Sufficiency of the Fibre Evidence
55 The deceased's body was examined where it was found in the late afternoon, early evening of 2 April by Detective Senior Constable Layton (Layton). During the course of his examination, he observed that there were fibres adhering to the soles of the deceased's boots. The boots were otherwise clean and in good condition, except for some scuffing on the right sole which appeared to have been caused by the boot having rubbed on or against something and some wear around the heels of both boots. Layton removed the boots from the deceased and placed them in individual sealed plastic bags for later examination. He took the boots to the office of the Crime Scene Unit and there took a number of photographs of the boots and the fibres.
56 Layton said that the fibres did not fall off merely by shaking the boots. It was the Crown case that the fibres adhered by electrostatic force and by physical entrapment around the heel areas.
57 The presence of the CRX's carpet fibres on the boots was the only evidence of any contact that the deceased might have had with the appellant's motor vehicle. Accordingly, for the Crown to prove the guilt of the appellant in any one of the three ways for which it contended, it was necessary for it to establish beyond reasonable doubt that the fibres on the deceased's boots came only from the CRX and had transferred to the boots a short time before her body had been dumped just off the Wakehurst Parkway.
58 The appellant accepted that there were fibres on the deceased's boots which came from the CRX. The dispute both at trial and on appeal revolved around two issues: whether the black fibres came only from the CRX and the extent, or likely duration, of the adherence of the fibres to the boots.
59 At the time that Layton first observed the fibres, he did not know where they came from. However, as he considered they might be a potential source of evidence he took the steps to preserve the evidence in the manner indicated. A few days later, he removed a random selection of the fibres from the soles of the boots with a pair of tweezers and placed them in sterile jars, leaving "a considerable number of fibres on the shoe". The boots with the remaining adhering fibres were re-sealed for later examination.
60 On 5 April 1995, Layton took the fibres to Darrell Waight (Waight), an analyst employed at the division of Analytical Laboratories, Physical Evidence Section of the New South Wales Police Department for forensic testing.
61 Waight investigated the chemical composition of the fibres with infra-red spectroscopy and found there were 3 types of fibre: grey polypropylene, 7 denier blue polypropylene and 6 denier black polyester. "Denier" is a measurement of weight of fibre. Waight was not able to ascertain the denier of the grey fibres because of their small size. Six denier is a common weight for black polyester fibre and is the Australian industry standard for carpet in motor vehicle boot liners.
62 It is convenient to record at this point that five other "stray" fibres - including a purple woollen fibre and at least one cotton or rayon fibre - were also found on the boots. The presence of these fibres was considered a normal incidence of fibre adherence and played no part in the issues raised except in one respect in relation to the appellant's case on fibre adherence to which I shall refer later.
63 Waight counted the fibres found on the boots and calculated that they had adhered in proportions of 13.89 percent grey, 16.67 percent blue and 69.44 percent black. He also did a count of the number of fibres in a section of the CRX carpet. That count revealed proportions of 55.3 percent grey, 18.3 percent blue and 26.4 per cent black. This count was confirmed and accepted by Professor Griffith, the appellant's expert in textile technology.
64 There was a marked variance in the proportions of the three fibres found on the boots in Waight's count when compared to the proportions he counted in the carpet. In particular, significantly more black fibres were found on the boots, whereas, on the counts of the CRX carpet carried out by Waight and Griffith, the predominant fibre in the carpet was grey. This discrepancy was relied upon by the appellant to demonstrate the unlikelihood that all the black fibres came from one source.
65 Waight carried out the counts before he received the manufacturer's specification and, when compared, there was a wide discrepancy between the figures in the specification and the count of fibres on the boots. According to the manufacturer's specification, the CRX carpet was comprised of 60 percent grey polypropylene, 15 percent blue polypropylene and 25 percent black polyester. There were two different weights of grey fibre - one of 7 denier and the other of 15 denier. The blue fibre was 7 denier and the black was 6 denier weight.
66 However, the specifications did not nominate whether the percentage proportions of fibres were by weight or by number. If the specifications referred to the proportions by weight and not number, the mix of grey, blue and black fibre in the carpet more closely approximated the mix of fibre found on the deceased's boots. Dr Roberston, Director of Forensic Services, Australian Federal Police and Mr Cauce, a chartered textile technologist, both gave evidence that the specification related to weight. There was no evidence which contradicted this.
67 The appellant also contended that regardless of the proportions in the carpet itself, the proportion of fibres found on the boots bore no relationship to the degree of transference of the three types of fibre. This argument was based upon the results of scuffing tests carried out by Griffith. Griffith gave evidence that by scuffing the deceased's left boot and an identical right boot on the CRX carpet, he obtained a rate of transference of 68.8 percent of grey fibres, 22 percent of blue fibres and 9.2 percent of black fibres, demonstrating a significant discrepancy between the percentage of black fibres found on the boots and that obtained in these tests.
68 This evidence might have appeared compelling to the jury, except that it was discounted, if not discredited, in cross-examination. The proportional transferability suggested by this result was, it turned out, an aggregation of the results of a number of tests. When the results of the individual scuffing tests were analysed, there were significant variations in the take up of the number and type of fibres. This was consistent with the scuffing tests carried out by others, including Waight and Robertson, which showed that there was a significant variation in the transference of fibres on different occasions.
69 Griffith indeed conceded that the results of his test varied "as would be expected if a person walks on a carpet and takes up some fibres on one occasion and using the same feet, the same person, the same shoes on another occasion … different numbers of fibres [would be] collected". He also conceded that the results of his tests did not reveal any particular pattern of take up of fibres.
70 It was thus open to the jury to reject the argument that there was a discrepancy of any significance between the proportion of fibres in the carpet and on the boots.
71 However, there was an aspect of the evidence of the fibres as found on the deceased's boots which was not explicable by reference to the proportion of the fibres found in the carpet. There was a clump of thirteen black fibres on the outside rear heel on the right boot. On the outside rear area of the left heel ten black fibres and one grey fibre were retrieved. The appellant contended that the presence of these clumps indicated there was some other source for the fibres.
72 Waight disputed the likelihood that the black fibres came from a different source. He said:
"… the chance of finding three different types of fibres on somebody's shoe at random, and finding the same three different sorts of fibres in a single source, the percentages are astronomical."
73 He explained this further by reference to the clump of 10 black fibres and 1 grey fibre. He said that if the fibres were together it was likely they came from one source:
"Because it is most unlikely that there would be two different sorts of fibres together on the shoe coming from a separate source, on the work we have done."
74 It followed, on his reasoning, that if the clump came from the one source, it was more probable that all the black fibres would come from one source.
75 Dr Robertson did not deny the possibility that the black fibres could have come from an alternate source, but believed that the high variability in the results obtained from scuffing the boots was consistent with the fibres coming solely from the CRX. Dr Robertson said this variance in transfer was explicable on a number of bases. He agreed with Griffith that the variance was a normal feature of transference. There were, however, other reasons. Dr Robertson explained that the extent and proportion of transference also depended upon "what was available on the surface", which, he said might vary for a number of reasons.
76 First, in the various scuffing tests which Dr Robertson and those working with him conducted, there had been difficulty in counting the number of fibres transferred because "we found they came off not as single fibres but small groups or pools of fibre".
77 Secondly, the wear of the carpet was relevant.
78 Thirdly, the method of manufacture of the CRX carpet also dictated what fibres were available on the surface. The carpet comprised 2 different types of fibre - polypropylene and polyester. Polypropylene is more sensitive than polyester to shrinkage due to heat. The evidence established that heat was applied on a number of different occasions during the manufacture of his carpet. With the consequence that the polyester fibres were sometimes longer and therefore closer to the surface than the polypropylene fibres.
79 Fourthly, the finer fibres tended to be closer to the surface. The black polyester fibre was the finest of the fibres used in the CRX carpet. Finally, the manufacturing process itself, which was a needle punch process, is such that the different fibres will shed from it in variable proportions. Dr Robertson considered that this made it highly unlikely that the carpet will shed in proportion to its percentage composition.
80 This evidence was uncontradicted in the appellant's case.
81 The appellant's submission, that the Crown failed to address the proposition that the weight of the evidence was such that it was probable the black fibres came from more than one source, is, therefore, untenable. There was an abundance of evidence which addressed the issue.