Swan – Causation in murder and the ‘substantial cause’ test

Originally posted on Amicus on 18 March 2020.

The High Court handed down judgment today in Swan, dismissing an appeal from the NSWCCA.

The question on appeal was whether it was open to the jury – as one of three possible causation pathways – to conclude that the appellant’s attack on the victim substantially caused the death of the victim – where there was a decision not to engage in life saving treatment several months after the attack.

Factual background 

The appellant and an accomplice invaded the home of the elderly victim, inflicting severe, but non-fatal injuries. These injuries led to significant cognitive and physical decline and the victim was discharged from hospital to a high-care nursing home. Several months later the victim fell and was taken to hospital, where it was decided not to operate on a fractured hip. The victim subsequently died.

The issue on appeal  was whether the one of the three causation pathway put to the jury was open on the evidence (the other two were not problematic). In other words, would the third pathway establish causation, entitling the jury to convict?

The third causation pathway 

This pathway was ‘succinct[ly] and clear[ly]’ characterised by counsel for the appellant, (at [21]):

The assault by the appellant caused injuries to [the victim] that resulted in a low quality of life for him. This low quality of life was the reason that when [the victim] presented to hospital with a fractured hip a decision was made not to undertake surgery. [The victim] died as a result of that decision because the lack of surgery permitted the fat emboli to travel to his lungs. [this was the proximate cause of death].

For this pathway to be open to the jury, there needed to be evidence to support three propositions (at [36]):

(1) surgery … was available and would reasonably have been expected to be able to save [the victim’s] life;

(2) [A] decision [was made] that such available surgery should not be undertaken; and

(3) the decision was motivated by [the victim’s] low quality of life due to the assault rather than due to other, unrelated considerations. (emphasis added)

The law on causation 

Citing Royall, the Court recalled that an act will have (legally) caused the death of the victim where it is a ‘a substantial or significant cause of death’ or a ‘sufficiently substantial’ cause (at [24]). Moreover, an accused person may cause the death even where their ‘act was was not, by itself, necessary for the victim’s death but was instead “one of the conditions which were jointly necessary to produce the event”‘ (at [25], quoting Royall). Thus, an act may be legally causative where it contributed to circumstances that collectively caused the victim to die. This will be the case even if other conditions alone would have been sufficient to cause death.

The trial judge’s directions to the jury included observing that causation was in issue. The Court agreed with her Honour’s direction that the significant or substantial cause test ‘did not require that the acts of the appellant were the only cause of death, the most important cause of death or even the only important cause of death’ (at [27]).

The Court reiterated it’s deference in Baden-Clay to the jury as the ‘constitutional tribunal for deciding issues of fact.’ This meant that the pathway of causation would be open to the jury even if the evidence for that particular pathway was tenuous (at [35], see further Doney at [12] – [18]). In other words, whether to accept or reject the evidence is up to the jury.

So was the third causation pathway open?


As far at the first and second propositions were concerned, there was sufficient evidence before the jury to support the inference that these were true. Evidence for the first proposition was found in the expert evidence adduced it trial. This evidence reflected a range of view points, all of which accepted that surgery would have been reasonable expected to save the victim’s life.

Regarding the second proposition, there was limited direct evidence that such a decision had been made. However the inference that it had flowed from the earlier communications by the victim refusing for further treatment, his extraordinarily poor quality of life, and clinical notes directly suggesting that the victim’s son had opted for palliative rather than operative treatment.

Regarding the final proposition, the appellant argued that the Crown had not negatived a range other possible motivations for the decision not to operate – that is, motivations unrelated to the injuries suffered by the victim in the attack. However, the Court rejected this, observing that the jury is not required to ‘fillet … the factors within the decision-making process to attempt to isolate the relative contribution of some or all’ of them (at [46]). Rather the question is whether the ‘effects of the assault substantially or significantly contributed to the decision’ not to operate (at [46]).

In this respect the Court found that there was ample evidence to support such a conclusion, noting in particular that the victim had suffered severe cognitive decline as a result of the attack and that this decline was a ‘most important thing’ in deciding to withhold further treatment (at [47]).

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