[65] Of course, there will be circumstances in which post-offence conduct is incapable of being probative of guilt of the charged offence as opposed to a lesser alternative or, another count on the presentment where there is a multiple-count presentment or another offence where it is disclosed by the evidence. For example, if a case of murder were presented to a jury on the sole basis that the accused admitted that he killed the deceased unlawfully, but denied murder, and the only evidence of the killing, apart from the admission, was that the accused had fled the killing and initially denied involvement in it, the jury could not properly be satisfied that the accused was guilty of murder. On the limited evidence available, one could not exclude as a reasonable possibility that the accused was guilty of manslaughter or possibly some lesser included offence. And the jury would need to be so instructed.
[66] But in most murder cases the evidence is more extensive than that. Usually, the Crown presents evidence about the relationship if any between the deceased and the accused, the events leading up to the time of death, the place and time and the circumstances of the death, the means of killing and the cause of death, other injuries which may have been inflicted on the deceased and any injuries suffered by the accused in the course of the killing.
[67] Although the post-offence conduct may not be enough in itself to sustain an inference that an accused killed with intent to kill or cause really serious injury, as opposed to some lesser state of mind, such evidence, when combined with evidence of the accused's words and conduct before and during the killing and forensic evidence, may well satisfy the jury beyond reasonable doubt that the accused killed the deceased with murderous intent. And comparable reasoning is equally applicable in trials for other offences.
[68] In some cases, for example, there may be something about the exact terms of a lie which when matched against the known circumstances of the actus reus leads a jury to conclude beyond reasonable doubt that the accused had the necessary intent or mens rea. The point is aptly illustrated in the judgment of Heenan J in Meko v R. In other instances, there may be something about the precise circumstances of flight or the nature of other post-offence conduct which, when related to the circumstances and means by which the actus reus was committed, leads a jury more confidently to conclude that the accused must have had the necessary intent or mens rea. Yet again in other cases it may be a combination of those things with others of similar or disparate kinds, according to the facts of the case, or it may be something else among the myriad facts and circumstances which inform the context to human interaction. Examples can be multiplied.[44]