R v Guingab

Supreme Court of Victoria|2010-06-15|Before: T FORREST J

DNA - Admissibility - Section 137 Evidence Act 2008 - Probative value.

1 The accused, Danilo Guingab, is charged with one count of murder. The prosecution allege that on December 11 2007 the accused struck Luvina Dayang ("the deceased") with a blunt object to the head and then strangled her. Her body was found bound with blue nylon rope and wrapped in plastic garbage bags similarly bound in the front garden of 35 View Street Springvale South at 10.45am on 12 December 2007. Mr Chadwick, who appears with Ms McCrickard for the accused, has argued for the exclusion of two pieces of DNA evidence sought to be led by the prosecution. In very short compass it is alleged by the prosecution that the accused's DNA is found on (a) rope used to bind the plastic bags in which the deceased was wrapped and (b) a size 10½ black thong found within a metre of the deceased on the footpath outside the View Street address.

2 The Crown case is circumstantial. Any attempt to evaluate the relevance or probative worth of these two pieces of evidence can only be undertaken against the background of all the significant pieces of evidence that form the Crown case.

3 The deceased was a citizen of the Philippines. In 2006 she came to Australia as a tourist but soon commenced work in Sydney as a carer. She occasionally travelled to Melbourne, but spent most of her time in Sydney. By the time of her death she had overstayed her tourist visa.

4 The accused is also of Filipino descent. He has been resident in Australia since 1987 and as at December 2007 was working as a Registered Nurse at the Kingston Centre in Oakleigh. He lived with his wife and four young children at 940 Heatherton Road Springvale. The Crown allege that his domestic arrangements were unusual. They say that he maintained a homosexual relationship with a Filipino resident called Caloy Magno, a distant relative by de facto marriage of the deceased.

5 It was through that connection that the deceased met the accused in 2006. The deceased knew only a few other people in Melbourne; two of whom were Violeta Tolentino and Ivy Rivera. On 8 December 2008 the accused from Melbourne contacted the deceased in Sydney. It is alleged that he maintained to her that he had identified employment for her in Melbourne.

6 Early on 10 December 2006 the deceased arrived in Melbourne. She met Tolentino in South Yarra. Tolentino lent her $50. She then travelled to the accused's house, arriving there mid-morning. His wife went to work shortly after this. The deceased spent most of her time that Monday at the accused's house. She visited Rivera, who lived nearby, for a short time.

7 The deceased spent the night at the Guingab house, sleeping in the bedroom normally occupied by the accused's wife, Marivic Guingab. The accused slept in a separate bedroom. On the Tuesday 11 December Marivic Guingab left for work early. Tolentino spoke by telephone to the deceased at about 9.00am. The deceased said that the accused would take her to see about the job after he got out of bed.

8 Later that day at 2.30pm the deceased spoke by telephone to her daughter Yayo who resided in the Philippines. In a 15 minute conversation the deceased told her daughter that the accused was going to take her to see about the job that afternoon. This, the Crown say, is the last known conversation conducted by the deceased.

9 At 4.42pm on 11 December 2007 a text message was sent from the deceased's mobile telephone to Marivic Guingab. The message read:

"I'm going back to Sydney. Thank you. Danny said by cigarettes and $29 Vodafone prepaid. Thank you again".

Marivic Guingab tried to call the deceased after receiving this message, but there was no answer.

10 Another text message was sent from the deceased's mobile phone at about the same time to her daughter Yayo. It purported to advise her that the deceased was returning to Sydney. During the evening of 11 December a number of people attempted to call the deceased. Each time her phone rang out.

11 Later in the evening of 11 December another set of text messages was sent from the deceased's phone. One was to the phone of the accused saying, in essence, that she had been caught by the immigration police and that the penalty was $50,000. Another was to Yayo and set out that the deceased was liable for a financial penalty and that the money should be sent to the accused.

12 On 13 December, Yayo spoke to the accused. It is alleged the accused said that he didn't want anything to do with it because he didn't want to get involved with the immigration police. It is also alleged that the accused asked Yayo for mercy and forgiveness during that call, but that the accused did not say why he sought such clemency.

13 By the evening of 13 December the discovery of the deceased's body in View Street Springvale South had been broadcast on the evening television news. Phone calls were exchanged between the accused and some of the deceased's friends. Discussion occurred about whether the body was that of Luvina Dayang. On 14 December, news bulletins published pictures of the deceased's clothing. The accused told some of the deceased's friends that that clothing was the same as the deceased had worn when she left his house. Marivic Guingab alleges that the accused told her at about this time he would report the matter to the police. He subsequently reported to her that he'd sent a text message to a sheriff's officer about the body. A text message was in fact sent from a public telephone to a sheriff's officer at 11.00 am on 14 December 2007 advising of the deceased's identity, that she was an illegal immigrant and that she lived in Sydney. By the evening of 14 December the police identified the body of the deceased.

14 On 15 December 2007 a search warrant was executed at the deceased's home. They found two plastic bags in a kitchen drawer which appeared very similar to the garbage bags in which the body was wrapped. The accused was interviewed. He told the police that the deceased had turned up unexpectedly on 10 December looking for work in Melbourne. She stayed overnight and on 11 December they chatted during the day. She received numerous phone calls and messages and at about 3.00 pm after a phone call she told him she was going to return to Sydney. The accused told the police that she left his house at about that time and that he did not see her again. He said he picked up his children from school at 3.30 pm.

15 The Crown case is that four of the seven bags used to wrap the deceased's body were identical to one of the bags taken by police from the accused's house and to bags supplied to the Kingston Centre by a company known as Able Plastics. These bags, the Crown maintain, are not available through retail outlets and are supplied predominantly to health care and pathology organisations. The Kingston Centre is one of Able Plastics largest clients. The Managing Director of Able Plastics alleges that several of the bags in which the deceased was wrapped were manufactured by his company. Marivic Guingab states she saw the accused handling blue nylon rope at the family home shortly prior to the disappearance of the deceased.

16 Thus, absent the evidence of DNA which I shall turn to shortly, the Crown case is built on a circumstantial foundation. The accused, the Crown say, was by his own admission the last person to see the deceased alive. Her body is found within 500 metres of his house. She was strangled to death and wrapped in bags which are identical to bags the accused, but not the general public, has access to. The text messages, it is said, are part of a ruse to deflect suspicion, and are highly suspicious in their own right. The accused is seen handling blue nylon rope on the evening of 11 December. The deceased is found trussed in blue nylon rope the next morning.

17 Many items were tested for DNA and results obtained. The prosecution seek to lead evidence of DNA found on two items only:

(a) the right thong and

(b) the blue nylon rope.

18 On 13 December 2007, Stephen Fowler, a Forensic Scientist at Victoria Police Forensic Services Centre (VPFSC), received item 11, a pair of black thongs in a bag labelled "Marker 9 View Road". The right thong has become item 11.1.

19 Item 11.1 was sampled in an attempt to collect biological material. Mr Fowler concluded that the sample gave a mixed DNA profile with contributions from at least two individuals. The mixture was such that it could be separated into major and minor components. The DNA profile from the major component matched the DNA profile from Danilo Guingab. The DNA profile from the minor contributor was too partial for comparison purposes. For reasons that will become apparent, Mr Fowler's statistical analysis of this DNA profile and its conversion into a Likelihood Ratio is no longer relevant.

20 Ms Lisa Federle, a forensic scientist with VPFSC, has provided a different statistical evaluation of item 11.1 as a result of changed VPFSC methodology. It is 110 billion times more likely that the DNA profiles from the major component of DNA detected on item 11.1 originated from Danilo Guingab than from some person chosen at random from the Australian Caucasian population. This proposition is stated with a 99% probability. This, Ms Federle opines, provides extremely strong support for the proposition that the major component of DNA on the right thong originated from Danilo Guingab. Using Filipino population sample data the likelihood ratio is four billion expressed to the same degree of certainty. Other population sample databases when applied, return Likelihood Ratios in the billions.

21 Samples were taken from five areas of the blue nylon rope. The Crown seek to lead evidence in relation to "Area 2". Initially, Mr Fowler expressed the opinion that this sample gave a partial mixed DNA profile with contributions from at least two individuals. Luvina Dayang and Danilo Guingab could not be excluded as contributors to this DNA profile. It was inconclusive as to whether Marivic Guingab could have contributed to this partial mixed DNA profile.

22 The interpretation of DNA profile of Item 21 Area 2 ("Item 21.2") has changed. Changes to DNA profile interpretation and reporting at VPFSC have been introduced since Mr Fowler conducted his analysis.[1] Ms Lisa Federle, a Forensic Scientist, at VPFSC, has conducted a further interpretation of Item 21 using "the VPFSC modified DNA interpretation methodology"[2]. The Crown seek to lead the following evidence from her in relation to Item 21.2:

• A partial mixed profile containing low levels of DNA was obtained from this sample.

• This profile has originated from at least two people.

• Luvina Dayang, Danilo Guingab and Marivic Guingab are not excluded as contributors to the DNA detected.

• A contribution of DNA from Luvina Dayang and Danilo Guingab would be sufficient to account for all the DNA types detected.

• A contribution from Danilo Guingab and Marinic Guingab would be sufficient to account for all the DNA types detected.

23 The prosecution seek to lead statistical analyses arising from this interpretation. They advance Likelihood Ratios that attach to three hypotheses which I shall set out below. They also seek to adduce evidence of slightly different Likelihood Ratios arising from the same hypotheses but using different sample population databases within the calculations.

(i) Either the DNA originated from Luvina Dayang and Danilo Guingab or it originated from two other people chosen at random from the Filipino population. With 99% probability and using the Filipino population sample data (FPSD), the minimum value of the Llikelihood Ratio is 38. That is, it is expected that it is 38 times more likely that the DNA profile would occur if it originated from Luvina Dayang and Danilo Guingab than two people chosen at random from the Filipino population.

(ii) Either the DNA originated from Danilo Guingab and Marivic Guingab or it originated from two other people chosen at random. Using the Filipino population sample data with 99% probability, the minimum value of the Likelihood Ratio is 48; that is it is expected that it is 48 times more likely that the DNA profile would occur if it originated from Danilo Guingab and Marivic Guingab than from two other people chosen at random from the Filipino population.

(iii) Luvina Dayang has contributed to the DNA detected. The other contributor is either Danilo Guingab or another person chosen at random. With 99% certainty and using the Filipino population sample data the Likelihood Ratio is 63. That is, that it is at least 63 times more likely that the other contributor of DNA on the rope is Danilo Guingab than some other randomly chosen person.

25 As I have observed the prosecution wish to lead evidence relating to these three hypotheses of statistical calculations relating to four databases:

(1) The Filipino population sample database (FDB),

(2) The Victorian Asian Database (VADB),

(3) The Australian Asian Database (AADB),

(4) The Australian Caucasian Database (ACDB).

Applying the differing databases to the latter three hypotheses above the following likelihood ratios are calculated.

All of these Likelihood Ratios are expressed to a 99% level of certainty and all are predicated on the specific assumption that there were only two contributors to the DNA found.

26 The evidence and submissions pertaining to this preliminary argument occupied ten sitting days and eight hundred and thirty eight pages of transcript. The prosecution called three witnesses, Mr Stephen Fowler, Ms Lisa Federle and Ms Dionne Prince (a scientist also employed at VPFSC). The defence called Dr Brian McDonald, a consultant molecular geneticist.

27 Mr Chadwick submitted, on behalf of the accused, that evidence relating to Items 11.1 and 21.2, ought be excluded on three general bases:

The evidence relating to item 11.1 (the right thong) is irrelevant, as comprehended by S 55 of the Evidence Act 2008 ('the Act').
That evidence relating to Item 11.1 has a probative value that it outweighed by the danger of prejudice to the accused and accordingly must be excluded (S 137, the Act). He makes the same argument in relation to Item 21.2.
That I should exercise the discretion conferred upon me by s 135 of the Act and refuse to admit either piece of evidence as its probative value is substantially outweighed by the danger that the evidence might be unfairly prejudicial to the accused.[3]

28 Thus it is necessary to conduct an assessment of the evidence sought to be led, its reliability and its proposed place within the Crown case. It is convenient to consider the arguments as they relate to the two items individually as the arguments differ in various ways. I should observe at the outset what I described in discussion with counsel as "the default position". It is this. If the evidence discloses no more than a differing of reasonably held scientific opinions about matters that are clearly within a jury's capacity to comprehend, then it is appropriate that the jury resolve that scientific dispute.[4]

Put another way, assuming the evidence is relevant,[5] I would need to be persuaded positively that the evidence sought to be adduced by the Crown was lacking in probative value:

(a) where it is outweighed by the danger of unfair prejudice to the accused (s 137 of the Act); or

(b) where it is substantially outweighed by the chance that the evidence may be unfairly prejudicial to the accused (s 135 of the Act).

29 I shall consider items 11.1 and 21.2 separately.

30 The defence contend that evidence that the accused's DNA was found on a thong found proximate to the deceased's body is irrelevant. It contends that even if it is the accused's DNA, it does not place the accused at the scene where the body was found. Thongs are portable, so the argument goes. The deceased stayed at the accused's house. She was shoeless when found, although wearing socks The jury may conclude that the accused had, at some stage, worn that thong but it could not say when. The deceased was a guest in the accused's house within hours of her body being found. The thong, so Mr Chadwick argued, no more placed the accused at the View Street crime scene than it did for any other contributor to the DNA material found on the thong.[6] Mr Chadwick submits that its probative value is therefore nil and accordingly it is irrelevant.[7]

I consider this evidence is relevant to the prosecution case. I have earlier adverted to the circumstantial nature of the case against Mr Guingab. I consider it is highly unlikely that the thongs were somehow transported to the crime scene by the deceased.[8] It is overwhelmingly likely that she was killed elsewhere and placed by one or more people at View Street. She was found wearing socks but no shoes and more importantly, her body was completely wrapped in plastic disposable garbage bags. It is open to the jury to conclude that the thongs must have been worn by the accused at some recent time (his DNA was found under one of the thong straps). It is open to the jury to conclude that someone wore the thongs to View Street and left them proximate to the deceased's body. In conjunction with the other evidence, I consider it is open to a jury to conclude that that person was the accused. It is capable of demonstrating that he was at the scene in the same way that if his driver's licence or his watch were found at the crime scene it would give rise to that conclusion. I consider that it adds to the united force of the evidence in this case and that it is capable of rationally affecting a jury's assessment of a fact in issue in the proceeding, namely that the accused was present at the place where the deceased's body was located.

31 Mr Chadwick contended that Item 11.1 was contaminated and thus of no probative worth. There is no doubt that the accused bears an onus in relation to the contamination issue, although I do not consider that it is as high as having to demonstrate actual contamination. It is sufficient, in my view, for the accused to prove that there is a real chance that Item 11.1 was contaminated either before or during the testing process. By "real chance" I mean more than a merely theoretical chance of contamination and one that is sufficiently high as to either eliminate or substantially erode the probative worth of the evidence. Should the accused prove that the probative worth is eliminated, the evidence is irrelevant and will be excluded. Should he demonstrate that its probative worth is substantially eroded, then its residual worth will need to be assessed against the unfair prejudice considerations as set out in s 137 and s 135 of the Act.

32 It is necessary to set out a summary of the testing process for Item 11.1. It was not until the sixth test of Item 11.1 that DNA was detected. This is because the sample was dirty and so the presence of "inhibitors" masked the presence of DNA. Five "cleanups" were conducted of the sample before results were found. Each test involved placing a tiny amount of the material extracted from Item 11.1 into a well on a plate. The plate contained ninety six wells, most of which received either standard solutions or material to be tested for DNA relating to a variety of cases. To load the wells, marked sealed tubes would be retrieved from a refrigerator. They would be arranged in a rack in the same formation as they were to be placed in the plate.[9] Each tube would then individually be taken from the rack, opened, two microlitres would be removed from the tube using a "pipette"[10] and placed in the appropriate well. Simultaneously the tube would be closed and placed back in the rack.

33 In substance, the accused points to the following:

(a) It is asserted that there is insufficient evidence before the court to explain where, how and with what other items Item 11.1 was stored before and between bouts of examination;

(b) The sample taken from Item 11.1 was initially very dirty, resulting in inhibitors masking the potential presence of DNA. Five separate "clean ups"[11] were conducted and the product then tested for DNA before it was detected on the sixth test;

(c) During the fourth test (run 268) the 11.1 sample was tested as part of the same run as a covert sample[12] of the accused's DNA. This, it is said, gives rise to the spectre of actual contamination between the samples;

(d) It is asserted by Dr McDonald that during the loading for tray 268, sample 11.1 was handled in such a way as allowed for contamination;

(e) The fact that the accused's DNA was found only after this 4th run is some evidence that contamination occurred during that 4th run or is at least consistent with that occurring;

(f) No confirmatory testing was done after the positive result from the 6th test. Given the level of allele peaks used by VPFSC, the accused argued that reproducibility was essential.

34 Evidence relating to the potential for contamination occupied a substantial proportion of all evidence adduced during the preliminary arguments. Ultimately, Dr McDonald conceded that if there were to be contamination, the most likely occasion upon which it could have arisen was during the loading of the plate for the fourth test. The plate contained 96 separate wells.[13] Sixteen wells were loaded with standard solutions. Sixty seven wells were then loaded with various DNA samples for testing. Eleven further wells were then loaded with other substances, irrelevant for present purposes. The covert sample[14] was the twelfth sample loaded in its well. It was loaded by using a pipette which was used to extract a tiny amount from the test tube in which the sample was stored. Ms Prince described the process by which samples of the DNA extract were loaded for quantitative testing:

... the samples are stored in a specific fridge located in the DNA science area...[15]

... The samples that are listed on this sheet[16] are the samples that have been added to the plate...[17]

... (In the fridge) the DNA extract is a liquid that's placed in a tube and the tube has specific labelling on it and these tubes are placed on a rack which is on a shelf [18].

... When I've gone to pick up these samples, I've placed them (in a rack) in the order of the sample sheet...[19]

... Item 11.1 was extracted on 14 December 2007[20]

... I'd go to the quantification rack based on what's on the sample sheet and position them into the rack according to what position I'd load them onto the plate...[21]

... First you set up the samples that require quantification in a rack in the order of where they will be loaded onto the plate[22]...and then you would actually load those samples onto the...plate....

... all transfer steps are witnessed by another analyst who is authorised ...to ensure that the correct samples are being loaded in the correct positions on the plate...[23]

... (The sample tubes) are always capped [24]

I'd then go and set up the 7500 plate. The setup is performed in a isolated area in its own separate hood. Prior to use of the hood it is decontaminated with hydrochloride...[25]

I would set up the actual plate which is a sterile plastic plate which contains the 96 wells...

two microlitres (are) taken out of the tube and placed in the well....[26]

only one tube is handled at any given time...I would open that tube. I would use the pipette which is the instrument used to measure volume and on top of the end of the pipette a tip is placed, which is a sterile tip and which is only used once...[27]

I would take two microlitres from that tube. I would close that tube immediately and place it back into the rack and place the two microlitres of sample into the relevant position that it is required in...[28]

35 Thus, Ms Prince described a process whereby each tube is sealed at the top, opened to extract a tiny amount for loading on the plate using the pipette and then closed immediately and replaced in its position on the "intermediate rack".

36 Any contamination as between wells on the plate is irrelevant for present purposes as the contents of every well tested were destroyed after testing, and the results of the testing for this run (as far as 11.1 was concerned), were negative, but with further clean ups suggested. Thus, the only potential for contamination during this testing process above and beyond the background risk in every laboratory is if, somehow, some of the contents of the tube containing extract from the covert sample (Item 28A-1) entered the tube containing the extract from Item 11.1.

37 As I have said, the covert sample was the twelfth sample loaded. The right thong sample (from Item 11.1) was the fifty eighth sample loaded.[29] There were, therefore, forty five separate samples loaded between samples 28A-1 and sample 11.1. It follows that there were forty five separate tubes opened for a short time and then closed between Items 28-1 and 11.1 being opened and closed themselves. There is no evidence that any other item being tested during this run was contaminated by sample 28A.

38 Dr McDonald criticised the procedure of running a covert sample with an evidentiary sample in the same test. A covert sample is similar in nature to a reference sample in that it is demonstrably the product of a sample taken from a suspect. It should, therefore, be treated in the same way, he argued, as a reference sample and be kept completely isolated from any evidentiary samples such as 11.1. There is some force in this argument, but it avoids the ultimate question. On this occasion and in relation to these two samples, is there a real chance of contamination?

39 I have concluded that whilst it may be desirable (and I consider it is desirable) to isolate covert samples from evidentiary samples completely, there is no evidence to suggest that on this occasion there is a substantially elevated risk of contamination of Tube 11.1 with some of the contents of Tube 28A-1. Mr Chadwick pointed to Ms Prince's evidence that she wore the same laboratory coat for about a week[30] and that she did not change her disposable gloves between each sample.

40 Ms Prince did state, however, that she changed her gloves frequently during the loading procedure[31] and she thought it unlikely that she would be wearing the same gloves whilst loading the two relevant samples.

41 Mr Fowler's evidence on this aspect was, I consider, thoughtful and measured:

Given my assessment of the situation, and given that this particular run was the only instant in my opinion where there was a possible contamination event, I have considered that in reference to the other possibility which that DNA was present all along; with my knowledge and of this procedure and as I discussed earlier, about the no two tubes being open at the same time, and considering how many samples there were in between, I believe there is a very minimal opportunity for a contamination event to occur at this stage of the process, and given that is the only opportunity, in my opinion, for the contamination to have occurred, I do not believe that is the case. Whereas, in reference to all the clean-up attempts and the UD with asterisk, in my opinion that is just consistent with it being a very dirty sample that required many clean-ups and there may well have been DNA present all along. While I cannot give 100% assurance, as I never can, in my opinion, I feel it is likely the DNA was present all along.[32]

In his written submissions, Mr Chadwick argued there was "insufficient evidence before the Court to explain where, how, and with what other items Item 11.1 (that is the physical thong itself) was stored between bouts of examination". The evidence is that it was only examined once for the purposes of swabbing for DNA material.[33] No issue of any moment was made of the pre-examination storage conditions.
Mr Chadwick further argued that once DNA was detected after the sixth test, it should have been tested again. He relied on Dr McDonald's evidence to the effect that reproducibility equates to reliability. Ms Federle and Mr Fowler disagreed with Dr McDonald on the desirability of further testing. They stated that the VPFSC minimum peak allele levels were such (at 50) Rfus that the result was reliable. Minimum peak allele levels have recently been raised from 40 to 50 Rfus. I accept that scientific opinions may differ on the desirability of reproducibility. I do not consider that the failure to retest after the sixth test, taken alone or in combination with the other evidence relating to contamination demonstrates a significantly elevated risk of contamination sufficient to justify intervention by the Court.

44 In this case, criticism is made by the defence of the databases used by Ms Federle to calculate Likelihood Ratios. The prosecution seeks to lead evidence of likelihood of the major contributor to the DNA found on the right thong being the accused's, as compared to another randomly chosen member of:

(a) The Australian Causasian community (using the Australian Caucasian Database - "ACDB"; or

(b) The Australian Asian community (using the Australian Asian Database - "AADB);

(d) The Filipino Community (using the Filipino database).[34]

• The VADB is too small (74 to 83 people) to be relied upon, and given that the member of individuals is expressed as a range, it is to be inferred that testing of those individuals did not disclose results at all loci tested;

• It is asserted that the de facto standard size of a valid database that ought be applied is 200 individuals, before any database can produce statistically reliable results;[35]

• The Filipino database (FDB) is derived from an article published in Legal Medicine[36] and was unknown to VPFSC until very recently. It has not been validated by them. Additionally, the results were obtained using the "Identifiler system"(which examines sixteen loci) as opposed to the Profiler Plus system which examines nine loci. The Profiler Plus system is the system used by VPFSC. Both systems are methods for amplifying genomic DNA. All nine loci from which data is collated under the Profiler Plus system are part of the 16 loci used in the Identifiler system;

• The Australian Asian Database ("AADB") is based on a published article. This article (so the argument runs) is to be preferred over a similar database found in Exhibit C, an unpublished article. If the published article is preferred, it can be discounted "as not an authority for anything" because of a typographical error that "has been undetected for years";

• The VADB and AADBs are taken from a broad cross-section of Asian people from the whole of South East Asia. The accused is Filipino and the data derived from the broader Asia bases is accordingly inappropriately used in this case;

• The Australian Caucasian Database (ACDB) similarly is inappropriate for use in this case because the accused is of Filipino origin.

46 I do not consider there is any great merit to these arguments. Evidence that was essentially uncontradicted was given by Ms Federle to the following effect:

• Provided an allowance is made in the ultimate calculation of the Likelihood Ratio for "sampling error" any deficiencies in the size of the database are eliminated;

• Provided an allowance is made for relatedness by incorporating into the ultimate calculation a FST factor (or "theta" value) any variations that are peculiar to particular ethnic communities are eliminated;[37]

• The FST value applied in this case was at such a level that the interpretations were biased conservatively in favour of the accused.

47 I note that, when pressed, even Dr McDonald could not identify error in the statistical approach of Ms Federle.[38]

48 As I have observed, the defence are critical of the use of the VADB, ACDB, and AADB on the basis that the accused is a Filipino. In my view, it is legitimate for the prosecution to seek to lead evidence of likelihood ratios from all four databases. The likelihood ratio by its nature expresses chance by comparing two individuals - the accused and another random person. The other random person is the alternative major contributor to the DNA. The other random person could be Caucasian or Asian (including of Filipino descent). The results, regardless of whichever database is used, are remarkably similar. I consider that the prosecution is also entitled to lead evidence of likelihood ratios from all these databases in order to meet the anticipated criticism from the defence that one or other of them are used inappropriately.

49 It is argued that the processes used to analyse DNA profiles obtained from both Items 11.1 and 21.2 is flawed. This argument is largely directed to Item 21.2 (the rope) where only low levels of DNA were detected. I shall return to it when I consider the argument relevant to that item. Insofar as Item 11.1 is concerned, Dr McDonald effectively conceded that the major contributor to the DNA detected was the accused. His major argument in relation to this item was contamination and the databases used for statistical analysis, both of which I have dealt with.

50 It follows that I consider that the evidence sought to be adduced of the collection, processing, and statistical evaluation in relation to Item 11.1 is relevant and I am not persuaded that its probative value is diminished to such an extent that it must be excluded (s 137 of the Act) or that I ought exclude it in the exercise of my discretion. I consider that the various criticisms made of the VPFSL analysis and interpretation are matters that are capable of being comprehended by a jury, and eventually amount to disputes between experts on these issues. In my view, it is appropriate that a jury try these disputes.

52 It is abundantly clear that this evidence is relevant. If the accused's DNA is on the blue nylon rope used to tie up the deceased then this amounts to very powerful evidence by itself that he at the very least assisted in the disposal of the body. Given that neck ligature marks were observed by the pathologist and that the cause of death was neck compression its relevance may extend to issues well beyond mere disposal of the body.

53 The starting point for an evaluation of the arguments relating to this item is that its probative value, taken at its highest for the prosecution[39] is very substantially lower than that of Item 11. The likelihood ratios of some of the DNA found on the rope belonging to the accused are expressed in double figures rather than in billions.[40] The ultimate opinion of Ms Federle is that the evidence provides moderate support for the various propositions that include Danilo Guingab as a contributor to the DNA found on Item 21.2. This is to be compared to the "extremely strong support" opinion offered in relation to Item 11.

54 Item 21.2 was tested twice. On both occasions it revealed a very weak DNA. It is common ground that low levels of DNA can lead to difficulties in the extraction and analysis processes. Misleading results can be obtained as the result of phenomena such as drop in, drop out, abnormal stutter peaks and the impact of stochastic (random) effects.

55 I set out here tables showing the accused's DNA profile and the results obtained from the two analyses of the rope.

56 From the beginning of 2010 VPFSC does not now combine the results of the testing but only uses the results of the test which contains the most information, in this case the first test.[41] The minimum Rfu[42] value at which an allele peak will be determined has been raised from 40 to 50 Rfu.

57 There is a good deal of common ground between Dr McDonald and Ms Federle.

(i) The DNA found at 21.2 originated from at least two people. There may be more than two contributors.

(ii) The accused, his wife and the deceased are not excluded as contributors.

(iii) A contribution from the accused and the deceased would be sufficient to account for all the DNA found at 21.2.

(iv) A contribution from the accused and his wife would be sufficient for all the DNA found at 21.2.

(v) If it is assumed there are only two contributors, and if it assumed one of those is the deceased the accused cannot be excluded as the other contributor.

58 The experts parted company on the fundamental assumption that underpinned all the hypotheses that were then subjected to statistical analysis. It will be recalled that the three different hypotheses were all predicated upon the assumption that the DNA found belonged only to two people.[43]

59 Dr McDonald argued in essence where levels of DNA were so low that there is not clear evidence of the number of contributors then the assumption that there are only two contributors cannot safely be made. He said there are high levels of drop out[44] when DNA levels are low and in this case that is evidenced by the drop out apparent in the second sample.

60 Mr Horgan argues that the approach taken by Ms Federle is reasonable and proper. She has applied a factor to account for drop out in her statistical analysis (a SPURS factor) and what is disclosed is simply a difference in scientific opinion well capable of being understood by the jury. Ms Federle said that, in part, the low likelihood ratios obtained were explained by allowing for drop out in her calculations.[45]

61 As I have observed earlier I am satisfied this evidence is relevant to a fact in issue in this case. The issues then becomes whether the accused has demonstrated that the probative value is such

(a) that it is outweighed by the danger of unfair prejudice to the accused (s 137 of the Act); or

(b) where it is substantially outweighed by the chance that the evidence may be unfairly prejudicial to the accused (s 135 of the Act).

62 The words "probative value" are defined in the dictionary as follows:

"Probative value of evidence means the extent to which the evidence could rationally affect the assessment of the probability of the existence of a fact in issue"

I consider that the use of the word "could" in this definition is a clear indication that ordinarily the evidence ought be assessed at its highest for the prosecution[46] and that considerations of credibility and reliability have a very limited operation in this sort of application[47]. The probative value of the evidence ultimately requires the court to perform an evaluation of the extent to which the impugned evidence properly advances the Crown case. There is no doubt that if the jury accept that the accused's DNA is on the rope the Crown case is advanced very considerably in the way I have outlined in paragraph 52. That is only part of the evaluative process. Taken at its highest for the Crown and accepting that there is the DNA of only two people on the rope there is "moderate support" for the proposition that part of the DNA on Item 21.2 belongs to the accused. Also taken at its highest for the Crown there may be more than two contributors and the likelihood ratio is expressed to 99% confidence.

63 Section 137 of the Act refers to the "danger of unfair prejudice to the accused". This involves more than mere hypothetical risk. It involves "a real risk of unfair prejudice to the defendant by reason of the admission of the evidence complained of".[48]

64 I consider there is a real risk of unfair prejudice to the accused if this evidence is permitted to be adduced.

(a) This is evidence that is capable of placing the accused at the scene of the disposal of the body. This of course is detrimental to the defence case but is not per se unfair.

(b) I consider that the likelihood ratios expressed and the qualifications that must be placed upon them are such as to moderate the probative value of the evidence very substantially.

(c) I consider there is a real danger that a jury would use this evidence to prove more than it does. DNA evidence is no longer novel.[49] It is well accepted as a legitimate and reliable scientific aid to criminal investigation. The danger in this case is that the jury will ignore the very low likelihood ratios and the fact that they are expressed on the contingency that the underlying assumption of only two contributors is correct, and then proceed on the basis that it is absolute proof that the accused bound up the body of the deceased with rope. In the crude language of the racetrack, on one view, there is a thirty seven to one chance that this is not the accused's DNA at all and even those odds are expressed on the contingency that there are no more than two contributors and to a certainty of 99%. In the DNA context Likelihood Ratios are usually expressed in the millions if not billions.

65 I do not consider that this danger can be adequately addressed by direction. If I exhort the jury to take real caution over its consideration of Item 21.2, this will only reinforce the "infallibility" of the results and statistical analyses relating to Item 11.1. Ultimately I am left with a distinct sense of unease about the probative value of this evidence and its capacity for unfairness to the accused. I consider the danger to the accused involves a real risk of unfair prejudice and I consider it outweighs the moderate probative value of the evidence.

66 For the reasons expressed above I will not admit the DNA evidence relating to Item 21.2 pursuant to s 137 of the Act. It follows that I need not consider s 135 of the Act. Were I called to do so I would have excluded the evidence relating to Item 21.2 in the exercise of the discretion granted me by that section and on the basis that there is a danger that the evidence might be unfairly prejudicial to the accused and that this consideration substantially outweighs the probative value of the evidence.

[1] See Exhibit 4. DNA Profile Interpretation Guidelines and Reporting. Method No 33.

[3] I do not understand the defence to be contending that s 135(b) or (c) are engaged.

[4] Pantoja 88 A Crim R 554 at 576 per Abadee J.

[5] The onus on this issue resting with the prosecution.

[6] It will be recalled that the prosecution allege that the DNA material found was mixed, with at least two contributors, the accused's DNA being the major contributor. The thong is size 10 ½ and physically obviously an adult thong.

[7] In that it is not capable of rationally affecting (directly or indirectly) the probability of the existence of a fact in issue in the proceeding. S 55 Evidence Act 2008.

[8] In his Record of Interview the accused stated that when he last saw the deceased she was wearing white rubber soled shoes (Q 1556).

[9] The plate is 12 wells wide and 8 wells deep.

[10] The pipette used sterile tips which were changed after each individual loading of a well.

[11] Using differing cleaning agents of varying strengths.

[12] The covert sample was of DNA extracted from a cigarette butt. It was demonstrably the accused's DNA.

[21] T 445. Thus a rack is loaded with tubes containing DNA extract in the same relative positions to each other as is required by the sample lineup (Exhibit G) for the loading of the plate for quantitative testing. The plate is a microfibre plate - T 446.

[29] Ms Prince said she loaded in the left to right order from the top as set out in Exhibit G.

[35] Mr Chadwick relies on a passage from Forensic DNA Evidence Interpretation Ex 2 in support of this proposition. I do not consider that the relevant portion of this exhibit supports this proposition (see page 272).

[38] T 674ff (re sampling error and FST values).

[39] I consider it appropriate to assess the probative value by assessing the evidence taken at its highest for the prosecution R v Linard Shamouil [2006] NSWCCA 112; (2006) 66 NSWLR 228.

[40] Those likelihood rations differ slightly depending on which database is used.

[41] Although the results of other less informative tests may be taken into account if there is additional information within them as to the number of contributors or their gender.

[42] Rfu is a unit of measurement used in electrophoreses methods using fluorescence detection.

[43] See paragraph [23] of these reasons.

[44] The failure to detect an allele within a sample or its failure to amplify during testing.

[46] See _R v Shamoui_l (2006) NSWLR 228 for a discussion of this issue c/f Papakosmas v The Queen (1999) CLR 297 at (86) per McHugh J.

[47] R v Cook [2004] NSWCCA per Simpson J. at (43).

[49] In the sense that it was at the time of R v Lucas [1992] VR 109.

At a glance

Court

Decision date

Before

Source

Judgment (135 paragraphs)

Parties

Cases Cited (1)