The reasoning of the trial judge
22Early on in his judgment the trial judge stated the test to be applied in determining whether or not to direct a verdict of acquittal. He referred to the principle as stated in Doney v The Queen [1990] HCA 51; (1990) 171 CLR 207 at 212 to the following effect:
"There is no doubt that it is a trial judge's duty to direct ... [a verdict of not guilty] if the evidence cannot sustain a guilty verdict or, as is commonly said, if there is no evidence upon which a jury could convict."
23His Honour accepted that "evidence which favours the accused as, for example, by contradicting, qualifying, or explaining the evidence supporting a conviction is to be disregarded: R v R (1989) 18 NSWLR 74", and that questions of credibility and reliability are for the jury to determine, not the judge. He stated the mere fact that in a circumstantial case it is possible to formulate a reasonable hypothesis consistent with innocence which the prosecution has failed to exclude cannot justify a direction that the jury should acquit if there is evidence upon which the accused could be convicted.
24The parties accepted that in this part of his judgment (pars [2]-[4]) the trial judge articulated the correct principles.
25The trial judge set out the evidence and summarised the Crown case in the following terms (at [18]):
"The Crown, in brief, submitted that the medical and scientific evidence, the timeline, the tension in the relationship, the lack of any other person with opportunity, what was heard by the neighbour and the statements of the accused permitted the inference that the deceased was strangled and/or hit over the head (either with the juicer bowl or otherwise) by the accused although it is unclear in which order these acts are said to have occurred. (Given that the accused was on trial for manslaughter and not murder, the possible financial gain that might have been a motive was not relied on.)"
26The critical portions of the trial judge's judgment are at pars [20]-[22]. It is convenient to set them out in full:
"[20] It is clear that identification of the cause of death or the precise acts that resulted in that cause need not be identified in every case, though it is obviously usually necessary to do so in order to show that it is the accused who was responsible. Here, the crucial question is whether the deceased's death was caused by the unlawful and dangerous act of the accused. There can be no doubt that answering this question requires focus on what the jury are able, as a matter of common sense and reason, to conclude from the evidence as a whole. The mere fact that the Crown case is possible could not, of course, justify a conviction. The evidence must be such that the accused could, though not necessarily would, lawfully be convicted upon it: May v O'Sullivan [1955] HCA 38; (1955) 92 CLR 654 at [7].
[21] It is important, indeed crucial, to understand that reasoning by inference is an essential part of the jury's consideration of the charge and that this may not always be capable of clear articulation, as is evidenced by the injunction frequently given that common sense has a significant part to play in drawing inferences. Of course, technical medical evidence is not a matter of common sense but of expertise, though its significance may well depend on common sense inferences derived from other material. That material, and how it impinges on or is affected by the medical evidence and, ultimately on the issues in the case, are matters for the jury to evaluate. Given the time frame in which it is possible that the injuries were suffered and the uncertainties of the cause of death, the surrounding circumstances - so far as there is evidence of them, are crucially important. Thus, for example, the juicer bowl may have inflicted the laceration to the deceased's chin, but was it wielded by the accused and, if so, in what circumstances? If he had used it, why did he leave it there in full sight and, if it were bloodstained, why was there no blood on the floor? If the deceased fell down the stairs why did the accused not mention it? This would require consideration, amongst other things, of his mental state at the time he spoke. If saucepans falling to the floor explains the noise heard by the neighbour, how did this happen and what inferences arose from it? Was it merely the sound of the juicer bowl hitting the floor and, if so (since it was thrown at the wall above the kitchen door), who threw it and why? Did it cause an injury to the deceased and, if so, in what circumstances? For example, did it cause any serious injury or one or more that was or were relevant to the deceased's death? Did the deceased fall down the stairs and could this event occur independently of the accused and, if not, did the accused do it deliberately or accidentally or in self defence? I mention these matters by way of example only - the range of factual issues is much wider of course. At the end of the day, one must remain acutely aware that inferences may be able to bridge any apparent gaps in the Crown case.
[22] Accepting, however, that there is no bright line separating 'conjecture' from common sense or inferential reasoning, the evidence must be such as to enable a lawful verdict of guilt. Much might be left uncertain but a judge must direct acquittal where, in his or her view, a guilty verdict would necessarily involve inadmissible conjecture. Inevitably, this will be a matter of fact and degree. In some cases, the multiplication of circumstances, taken together (though ignoring those matters that assist the accused), will be capable of leading to a conclusion of sufficient certainty to justify conviction, in which event, there is a case to answer. Here, however, the number of possibilities and the varying inferences available if one or another path of reasoning be followed add to uncertainty rather than reduce it. The choice of path is fraught with considerable doubt and each has substantial gaps. So far as the medical evidence pertaining to the event or events that caused death, a very significant complicating feature is the evidence, not given at the first trial, of the 24-hour time frame in which the injuries may have been suffered. Amongst other things, this made it distinctly less important than it earlier appeared that a fall down the stairs almost certainly did not explain all the injuries."