R v Niguidula (No 2)

1. [1]

   On 2 July 2021, the accused was arraigned before R A Hulme J on an indictment charging her as follows:

2. [2]

   The trial is due to commence before me on 9 May 2023.

3. [3]

   For the purpose of these reasons, it is unnecessary to set out the background to the allegations in any detail. It is sufficient to note that the deceased died as a result of a single stab wound to the chest in circumstances which give rise to an issue as to whether the wound was occasioned by an assailant (on the Crown case, the accused) or whether it may have been self-inflicted.

4. [4]

   The accused has raised an objection to the admissibility of evidence the Crown proposes to call from Professor Duflou. Professor Duflou is a well-known forensic pathologist. He has authored two reports in relation to this matter, the first dated 13 April 2023, and the second dated 20 April 2023. Both reports were tendered before me on the voir dire although the Crown has indicated its intention to rely only on the first report.

5. [5]

   The Crown intends to call Professor Duflou to provide expert evidence in relation to the question of whether the stab wound causing the death of the deceased was self-inflicted or inflicted by another person. For the purposes of this application, the first report is understood as setting out the evidence Professor Duflou will give. The accused raises no issue with the majority of the evidence sought to be led from Professor Duflou but objects to the final paragraph of the report which states: [1]

6. [6]

   No issue is raised as to the relevance of the above. The evidence is relevant to prove the accused inflicted the wound causing death (as opposed to the wound being self-inflicted). The evidence is evidence of an opinion which is ordinarily inadmissible: Evidence Act 1995 (NSW), s 76. Section 79(1) provides an exception to the exclusionary rule in s 76 where the evidence is given by a person who has “specialised knowledge based on persons training, study or opinion” and the opinion to be led is “wholly or substantially based on that knowledge”. On behalf of the Crown, it is submitted that the opinion is one to which s 79(1) applies.

7. [7]

   It is not an issue that Professor Duflou has “specialised knowledge” within s 79(1) of the Evidence Act, based on his study and his experience as a forensic pathologist. On this basis, it is accepted he is able to give the evidence set out in the earlier paragraphs of his report. It is however submitted that the final paragraph of the report is either not substantially based on his specialised knowledge, or alternatively it would be unfair to admit the evidence. While not expressed in the terms of the section, the alternative submission refers, by footnote, to s 137 of the Evidence Act.

Expert evidence

1. [8]

   Section 79(1) of the Evidence Act, provides:

2. [9]

   The specialised knowledge upon which the opinion is said to be wholly or substantially based relates to “differentiating self-inflicted from inflicted sharp force injuries”.

3. [10]

   In Honeysett v The Queen (2014) 253 CLR 122; [2014] HCA 29 the Court stated (at [23]):

4. [11]

   In R v Warwick (No.37) [2019] NSWSC 196 Garling J said (at [8]) (referring to Honeysett):

5. [12]

   The plurality in Dasreef Pty Ltd v Hawchar (2011) 243 CLR 588; [2011] HCA 21 noted uncontroversially (at [32]):

6. [13]

   Their Honours later observed (at [37]):

The report

1. [14]

   In his report, Professor Duflou sets out his training study and experience, his acceptance of the code of conduct, his understanding of the purpose of the report, and the material he received. He notes that he had not previously been involved in the investigation of this matter, nor personally examined the deceased at any time. Professor Duflou sets out his understanding of the circumstances in which the deceased was found, a summary of the autopsy report, a description of the knife that was found, and describes, from the photos supplied to him, the T-shirt the deceased was apparently wearing at the time he was stabbed.

2. [15]

   In his summary of the autopsy relied on by him, Professor Duflou says: [2]

3. [16]

   Later in the report, Professor Duflou notes that there were no hesitation marks or defence injuries. [3]

4. [17]

   In the critical section of his report, titled “differentiating self-inflicted from inflicted sharp force injuries”, [4] Professor Duflou expresses the opinion that “most forensic pathologists have training and experience in this area, and it is my experience that most forensic pathologist[s] are able to comment on whether a wound may be self-inflicted or not.” [5] While he does not explicitly include himself in this category, in context, he does so implicitly.

5. [18]

   Professor Duflou observes that there is “generally no single way of determining whether a wound has been self-inflicted or has been inflicted by an assailant”. [6] He notes the exception where an injury has been sustained to an area of the body the person would not themselves have been able to access. I pause to note that whether a person could or could not access an area is likely to be specific to the individual. Further, the conclusion that the wound was not self-inflicted on the basis that the person could not access that area themselves, would not appear to require expert evidence. This observation, to an extent, reflects the accused’s complaint with respect to Professor Duflou’s conclusion, a matter to which I will return.

6. [19]

   Professor Duflou makes the following general observations: [7]

   1. (1)

      “[s]elf-harm by sharp force is not uncommonly seen in forensic pathology practice, although the types of injuries sustained are more commonly in the form incised wounds, or slashes, rather than penetrating stab wounds”; and

   2. (2)

      he has “seen self-inflicted stab wounds on multiple occasions, many of which have had unusual or atypical features”.

7. [20]

   The above observations at the least, leave open self-infliction as a possibility with respect to the present case.

8. [21]

   Professor Duflou observes that there are various means of assessing a wound which can give indications as to how it was sustained. Professor Duflou then sets out a table (taken from a publication co-authored by Professor Duflou) which he says provides “one such approach to ascertain whether injuries sustained were the result of self-infliction or as a result of infliction by an assailant”. [8] The table is reproduced below: [9]

9. [22]

   No specific comment is made by Professor Duflou with respect to the table or its application to the deceased. My own observation is that the table alone does not appear to allow any conclusions to be drawn in the present case. With respect to the presence of “bruises and lacerations”, I note that the deceased was described as having multiple “superficial abrasions and bruises”, [10] however, it is then indicated in Professor Duflou’s summary that “many [of these] appeared to have been sustained some time prior to death”. [11] It is not clear whether there were any bruises or lacerations sustained that can be substantiated as having occurred around the same time as the fatal wound. Otherwise, the avoidance (if that accurately describes a case involving a single wound) of sensitive areas and the absence of defence injuries are factors in the column of matters characteristic of self-infliction.

10. [23]

    Having set out the above table without comment, Professor Duflou, sets out of the following statistics provided by research in this area: [12]

    1. (1)

       “stab wounds to the chest are seen in 36% of self-inflicted cases versus 54% of homicidal cases” (I note there is no explanation of the remaining 10% of cases);

    2. (2)

       “there was no significant difference … in the number of wounds” as between self-inflicted cases and homicidal cases, (I add, making it a neutral factor);

    3. (3)

       “clothing was penetrated by the weapon in roughly equal percentages” (again making this a neutral factor);

    4. (4)

       “hesitation marks were seen in just under half of self-infliction cases”; and

    5. (5)

       “‘defence wounds’ were present in 37% of homicides”.

11. [24]

    Again, no specific comment is made by Professor Duflou with respect to the above statistics. My own observation is that the fact the wound was to the chest points to homicide over self-infliction, such wounds being more common in homicide than self-infliction. While not explicitly stated, I interpolate that hesitation marks are, at least, less common in cases of homicide. On this assumption, the absence of hesitation marks does not support self-infliction, however, nor does it, on the statistical information available, provide strong support for homicide. The extent of any support is likely a matter for a mathematician appraised of more information.

12. [25]

    Professor Duflou then sets out the following observations based on his own experience: [13]

    1. (1)

       “intentional self-inflicted stab wounds to the chest are relatively uncommon” but he has seen multiple such cases;

    2. (2)

       hesitation wounds are “commonly seen in self-inflicted stab wounds” and uncommonly seen in wounds inflicted by an assailant;

    3. (3)

       “single self-inflicted stab wounds to the chest uncommonly pass through clothing, while such wounds [inflicted by the assailant] very commonly pass through the clothing should the person be wearing a shirt at the time”; and

    4. (4)

       “[l]ess commonly, the knife is left embedded in the lethal injury in [a case of] self-inflicted injury, while … a knife is almost never left in place in the wound in a person who has sustained an inflicted injury.”

13. [26]

    It might be noted that the above factors point to a conclusion that the wound was not self-inflicted. Some observations might be made. The first point can be compared with the statistics previously referred to above which provided a figure of 36% of stabbings to the chest as being self-inflicted, while 54% were by an assailant. The second point can be compared with the statistics which indicate hesitation marks in “just under half” of self-infliction cases. The third point can be compared with the statistics which suggest the penetration of clothing is a neutral factor. Professor Duflou’s experience is not necessarily inconsistent with that statistic as he is speaking of a single stab wound through clothing while the statistics are not specific as to this. But the comparison of Professor Duflou’s observation with the statistics highlights the difficulty in knowing what weight can be given to this factor in the absence of any understanding of the sample size Professor Duflou is drawing on. The fourth point similarly provides little assistance given it is not known how uncommon is for a knife to left in place in the wound. If it is rare, as Professor Duflou’s language suggests, the factor is largely neutral.

14. [27]

    Professor Duflou then concludes: [14]

15. [28]

    With respect to Professor Duflou, it is not clear how he reasons from the table, the statistics and his own experience to the finding that it is “much more likely” that the wound was inflicted by assailant. I accept that he refers to factors which point towards such a conclusion. However, at [23] he also refers to the absence of defensive injuries which is a factor in favour of self-infliction. The significance of this has obviously been discounted in the process of reaching the conclusion. However, there is no articulation of why. In short, there is no analysis of the weight to be given to the various factors and their interaction. The report does not explain how the conclusion has been reached by any process of reasoning “substantially” based on Professor Duflou’s specialised knowledge. Insofar as he relies on particular factors, it is not clear whether he is applying his expertise or is engaged in a more complex version of logic, such as the one referred to above, that is, a wound in a location unable to be reached by the victim is highly likely to be the result of an assailant.

16. [29]

    Admissibility of the relevant paragraph of Professor Duflou’s report is dependent upon my satisfaction that the opinion is substantially based on his specialised knowledge. I am not satisfied on the balance of probabilities that this is so: Evidence Act, s 142. That paragraph of the report is not admissible.

17. [30]

    Having regard to my conclusion above, it is not necessary to consider the application of s 137 to this evidence. I note, however, that even if I were to accept the opinion as substantially based on Professor Duflou’s specialised knowledge, I would have grave reservations in allowing it before the jury. Firstly, insofar as it is a conclusion drawn from various factors it will be necessary for the jury themselves to consider and understand those factors. The conclusion presented by a person with the authority of a highly qualified expert carries the risk that the jury (inevitably faced with a number of difficult issues to consider) will simply accept the conclusion without applying their own critical analysis. This concern is to be seen in the context of a conclusion expressed in the imprecise terms of “much more likely”. To give meaning to the expression, it is necessary to understand the individual factors. It is therefore preferable that the jury themselves understand those individual factors.

18. [31]

    I uphold the objection to paragraph [24] of the report of Professor Duflou of 13 April 2023.