R v Chandler

Judgment - Admissibility of opinion evidence of Ms Beilby, Forensic Biologist, in s 177 Evidence Act Certificate, dated 5 March 2014 1Objection has been taken to aspects of the proposed opinion evidence concerning aspects of 'DNA' investigations in this matter. Last Thursday 14 August 2014 the Court was advised by the parties of the need for a voir dire examination to determine the admissibility of evidence relating to the testing of a knife found after the robbery of the victim in this matter to ascertain the presence of DNA material which might be consistent with the DNA profile of the accused and/or the victim. I gave a ruling on the objection at the conclusion of the voir dire examination on Tuesday 19 August 2014. 2The knife was found at the rear of a block of premises a few streets away from the scene of the robbery apparently embedded in a mattress. Nearby were found items that had been removed from the wallet of the victim which were, as I understand it, clearly his property. 3Objection was made to the admissibility into evidence of an opinion, or opinions, expressed by Vivienne Beilby, a Senior Forensic Biologist with the NSW Forensic and Analytical Science Service, that a partial DNA profile recovered from the stained area on the right side of the blade of the knife was the same profile as the victim, and that this profile is expected to occur in fewer than one in one hundred billion individuals in the Australian population. This conclusion was reached by the use of the 'Promega Powerplex 21'kit, or system, for developing DNA profiles, introduced nationally in early 2013 to replace the "less sensitive" 'Profiler Plus' kit or system. I also understood that the objection related to the chain of possession of the knife from the time it was found by the police to the time it was delivered to the "DNA laboratory" of the NSW Forensic and Analytical Science Service ('FASS'), the chain of possession and testing of the knife, the manner of obtaining results from that testing and as to the factual assumptions upon which the opinion expressed by Ms Beilby in her report of 5 March 2014 was based. 4The opinion expressed by Ms Beilby was based upon testing that occurred in February 2014, after there had been testing undertaken at an earlier time which was unsuccessful. There was no issue about her study, experience and training. 5Initially (that is on 14 August 2014), I understood that objection was taken to an opinion expressed by another forensic biologist as to a match between the DNA profile of the accused and DNA material obtained from the handle of the same knife as a result of testing conducted between 21 January 2010 and the s 177 Certificate of Forensic Biologist Fiona Rose dated 13 November 2012. 6After a number of delays and staggered production of material by the prosecution, the voir dire examination was concluded on the afternoon of Tuesday 19 August 2014 with only one issue for the Court to resolve. The one matter left for the Court to determine, having on several occasions endeavoured to ensure that the particulars of the objection were clearly articulated, was the admissibility of the opinion of Ms Beilby in relation to the identification of the DNA profile recovered from the blade of the knife being the same profile as the victim's and the probability of that occurring. 7Additional statements obtained by the prosecution as well as 'working' documents of the laboratory, apparently all obtained by the prosecution after the trial was listed to start, removed from the Court's consideration the need to consider the chain of possession of the subject knife from the time it was found by police until the time it was delivered to the "DNA laboratory", the chain of possession and chain of testing occurring within the DNA laboratory and the results of that testing insofar as it produced relevant "markers" at particular 'loci' of DNA material identified from particular chromosomes, to enable a relevant comparison to be made between the DNA sample provided by the victim and the DNA material identified on the blade of the knife. No objection was pressed in respect of the testing for comparison purposes of the DNA sample given by the accused by way of buccal swab and the DNA material developed on the handle of the knife where a 'match' of 'markers' was established. 8For the purposes of this judgment I note the transcript that has been made available to the Court since the ruling was given relating to the discussion had with the Crown Prosecutor on the morning of 19 August 2014, when I asked her to lead me through the documentary material produced in dribs and drabs to explain to me what the relevant statements and working documents of the laboratory meant in the context of the objection as it was understood by the prosecution. 9It must be said, without me having to analyse it particularly, that in the context of the character of the objection identified by counsel for the accused, the respective certificates containing the opinion the subject of objection, and the supporting statements of Ms Beilby, did not reveal the factual assumptions upon which her opinion was based, nor identified from other material available in statements and working documents relevant matters taken into account by her in formulating her ultimate opinion. The Court learnt in the course of the discussion had with the Crown Prosecutor that in fact many of the matters submitted by her relating to the material in documentary form that had been tendered, particularly explaining the relevance of specific initials, processes, entries on working papers, computer printouts and the like, which were not self explanatory (some not even revealing dates when particular testing occurred), was based upon information provided to her at least by Ms Beilby in conference at an earlier time. The information provided by Ms Beilby at an earlier time to the Prosecutor in conference should have been provided to the defence, and if needs be to the Court, to inform both in relation to matters in respect of which there were significant self evident gaps or matters left unexplained in the documentary material. 10This was self evidently so when one has regard to the fact that counsel for the accused had made it quite clear that his objection to any relevant opinion based upon scientific testing (in fairness to the Crown at an early stage this was not isolated to the opinion of Ms Beilby) was concerned with issues that were discussed in two principal judgments: Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705, per Heydon JA (particularly at [85]), and R v Sing (2002) 54 NSWLR 31, particularly at [34] - [36] and [38]. 11The observations of Heydon JA in Makita are further discussed, in the context of the consideration of the admissibility of expert evidence and ss 79-80 Evidence Act 1995, in Keller v R [2006] NSWCCA 204 at [28] - [31]. The Crown referred to the Court to the decision to Sharwood [2006] NSWCCA 157, but the relevant passage cited by the Crown was of little further assistance. 12The essence of the objection is that the reports in their various forms of Ms Beilby did not reveal the basis upon which she had formed the relevant opinion the subject of objection, or what matters she took into account in coming to the conclusions that she did. It was submitted thus, that the evidence was opinion evidence that ought not be admitted because there was insufficient basis for her to express an opinion wholly or substantially based upon her training, study or experience. Thus, her opinions were not an exception to the rule of exclusion known as the "opinion rule" in the Evidence Act, and/or there were lacunae in the evidence such as to require the opinion expressed by Ms Beilby to be excluded pursuant to s 137 Evidence Act, as occurred in Sing (supra). 13As the matter was finally argued by counsel for the accused, this latter aspect fell away. It was submitted, in a nutshell, that the basis of Ms Beilby's reasoning for expressing the opinions concerning the matching, in a partial sense, of the respective DNA profiles and particularly the probabilities were not revealed. 14The "worksheets" annexed to the statement of Ms Beilby of 18 August 2014 included the documents identified by the Crown as those setting out the "markers" at particular "loci" (as that expression was explained by Ms Beilby in her oral evidence), represented as 'spikes' in the graphs produced (Exhibits H2 and H3 in the trial) that were located at particular chromosomes of the DNA profiles developed at the laboratory, or on particular parts of a chromosome. The oral evidence of the witness as to the individual characteristics of the markers that were identified sets out, in essence, the basis for the opinion expressed of a "match" of the two DNA profiles developed (one partially complete). It must be said that the "matching", once the relevant worksheets were explained, was self evident. Whether there were relevant 'mismatches' that excluded the complainant as the donor of the DNA located on the blade of the knife was not explored, explained, or commented upon by counsel for the accused on the issue of admissibility. 15The critical matter that emerged from the voir dire examination was the method of the calculation of probability. It is correct that the evidence of the witness, in conjunction with the documentary material, was dependant upon the use of computer program(s) that developed the data measuring probability of specific markers being identical, and ultimate probability of such a comparison occurring by reference to particular populations identified as "Aus Cauc", "Aus Aborig" and "Aus Asian". Those printouts, called "Conditional Probability Calculation Sheets", were annexures E 2/3/4 to Ms Beilby's latest statement (Exhibit H5 in the trial). The evidence of Ms Beilby was that in the context of well accepted statistical mechanisms for calculating probabilities, by reference to the combination of accepted "frequencies" for identical alleles or "markers" to be identified from two different DNA sources, whether the racial basis for analysis was Australian Caucasian, Australian Aboriginal or Australian Asian (the three accepted populations bases identified for comparison purposes) the mathematical probability in any case, given the character of the matches and the most conservative "confidence limit" for such a match to occur, as revealed by the mathematical probability expressed by Ms Beilby in her 'Certificate', was still very conservative. In other words the expression of the probability was not dependant upon the "racial" background of the DNA profile. 16The probability of matches, as were shown by the diagrammatic sheets in the markers for the DNA of the victim and the DNA profile developed from the blade of the knife, was explained by the witness as calculated by accepted statistical models. No suggestion was put that the calculations were in error or that the models were inherently unreliable or false. Nor was any evidence adduced, or suggestion made, that the "Powerplex 21" system for extracting and comparing DNA samples was inherently flawed. The revealed relevant facts observed by the expert, or the assumed or accepted facts providing the basis upon which the relevant opinion the subject of objection was expressed, should have been included in the Certificate Ms Beilby made on 5 March 2014. On the basis of that Certificate the point taken as to the admissibility of her opinions was initially well taken, but fell away with the evidence produced on the voir dire. 17Ms Beilby described in her oral testimony the process of "lysis" (the bursting open of cells to release the DNA, and cleaning it up): "quantification" identifying how much DNA is in the sample, whether none, too much or the optimum level: "amplification" the copying of the DNA developed, or the "amplifying" of it to test it, and the process of "Capillary Electrophoresis" (CE), which is the process that separates the necessary DNA fragments and permits the production of the graphs to show the "markers" upon which or from which comparisons can be made between different samples. The diagrams that were produced, such as D2 in the documents attached to Ms Beilby's statement, represent graphical representations of the results of the CE test. The computer printouts from that test reflect the consequence of the scientific examination of the DNA material, the results of which are analysed within the Powerplex 21 system, to ultimately produce the printouts earlier described (E 2/3/4) that identify both the frequency of particular alleles, within particular racial group profiles, and the mathematical probability of the combination of matches occurring within two separate samples. 18The actual working of the computer program that developed the "Conditional Probability Calculation Sheets", or the graphs for visual comparison, is not explained. But what the working sheets contain is the product of the program's consideration of the identified 'markers' which can clearly be seen in those graphs produced (H2 and H3) after the process referred to in other statements and the relevant "worksheets" (such as annexure D1/1 to Ms Beilby's August 2014 statement) as CE, conducted on the relevant samples by Khan Nguyen on 26 February 2014. Nothing has been raised during the voir dire to suggest those probabilities are wrong or misleading other than to say the calculations, or how they are based, are "opaque". 19The 'probability sheet' printouts are a representation of the working of the program, as discussed in the "Appendix" to the "Expert Certificate" of Ms Beilby of 5 March 2014, particularly at page 1-2 of that document. In relation to Powerplex 21 "statistics" the Appendix states: "they are calculated using a national frequency database specific that can be applied for Caucasians, Aborigines or Asians", as opposed to the more limited "Profiler Plus" statistics. The Appendix explains the manner in which the statistical comparison is undertaken. 20Having regard to the evidence of the witness as to the method of considering the statistical frequency of a particular combination of circumstances, in the context that there is no evidence that the method of calculating the frequency of particular or specific matches, or identifying particular matches, is unsound or unreliable, the evidence given on the voir dire (taking into account that the witness, if required to a jury, has the qualifications to explain fundamental terminology that was unnecessary in the absence of the jury) provides the relevant basis upon which the respective opinions the subject of objection are founded. I note that there was no dispute as to the expertise of the witness to express the various opinions that she did, or to give particular evidence interpreting the data available to her. 21As part of the voir dire material, a statement was tendered by the defence from Ms Jae Gerhardt a "Forensic Biologist" said to be an expert in relation to DNA extraction and identification. No issue was identified in submissions that arise from that statement. There was no suggestion made that there was material, or evidence, to suggest that the data available to Ms Beilby was inherently unreliable, or that any matter about which she gave oral evidence that formed the basis for her opinion ultimately expressed was not reasonably available for her, relying on the test results and the use of the "Powerplex 21" system to extract and compare DNA profiles and to calculate relevant probabilities having regard to different "racial" databases. Ms Gerhardt's ultimate opinions turn not upon the data relied upon by Ms Beilby arising from the use of the Powerplex 21 system, but on matters arising from the character of the sample tested on the blade, possible differences or discrepancies arising from the "low levels of DNA present", the significance of diminished alleles, and concern as to the characterisation of the staining on the blade (para 7.1, 7.2 Statement Ms Gerhardt 8 May 2014) 22Thus, I concluded that the evidence sought to be adduced from Ms Beilby is relevant, it is evidence that is admissible pursuant to s 79 as an exception to the opinion rule in the Evidence Act and the probative value of the evidence outweighs the danger of unfair prejudice (ss 135, 137 of the Act). No relevant unfair prejudice was identified in submissions in any event. Appropriate warnings will in due course be given to the jury.