Post-offence conduct refers to anything said or done by an accused after the commission of an offence. It comprises a vast array of words and conduct.
Post-offence conduct invokes a restrospectant chain of reasoning. The trier of fact is invited to infer from a subsequent act, state of mind, or state of affairs that a prior act was done or that a state of mind or of affairs existed at a material time in the past: R v Smith, 2016 ONCA 25 at para 76
When is it Probative?
Post-offence conduct evidence is circumstantial evidence which may be probative of guilt. There is no special rule governing when evidence of post-offence conduct will be probative of guilt. Its probative value depends on:
the totality of the evidence
the positions of the parties
the fact the proponent seeks to have inferred from that conduct
the issues at trial
the nature of the post-offence conduct,
The overriding question is this: what do "logic and human experience" suggest that a jury can legitimately or rationally infer from the accused's post-offence conduct? R v Moffit, 2015 ONCA 412 at para 41; R v Vant, 2015 ONCA 481 at paras 121-125; R v Pannu, 2015 ONCA 677 at para 125
Post offence conduct may be probative of an accused’s culpability but is usually not probative of the level of that culpability: R v Gayle, 2017 ONCA 297 at para 50
When to give a limiting instruction
A limiting instruction is required where a trier of fact may find the evidence of greater value than its intrinsic worth. This typically arises in respect of post-offence demeanor conduct: R v Pannu, 2015 ONCA 677 at paras 125-127
When to give a 'non probative value' instruction
When post-offence conduct has no probative value with respect to a particular issue, the jury should be so instructed.
The issue of a “no probative value” instruction frequently arises when the post-offence conduct evidence is equally consistent with two or more offences (e.g., murder and manslaughter). If so, the jury must not consider that evidence in determining which of the offences was committed: R v Moffit, 2015 ONCA 412 at paras 42-43
The "Hall" Error
It is an error for the trial judge to instruct the jury to determine whether the appellant acted as he did because he was conscious of having done what was alleged against him.
This employs tautological reasoning and invites the jury to jump directly to the issue of guilt as a pre-condition to the use of the evidence of post-offence conduct in determining whether guilt has been established. In other words, the jury is required to consider whether the accused was conscious that he committed the offence before they can use the post-offence conduct evidence to decide if he committed the offence: see generally R v Moffit, 2015 ONCA 412 at paras 53-55; R v Taylor, 2015 ONCA 448 at para 141, but see paras 142-143
Post-offence conduct and Homicide
Destruction of a body can be probative of intent if it is reasonable to infer the accused destroyed the body after causing that person’s death “because he knows that the victim suffered injuries that are inconsistent with a non-intentional cause of death”. The inference is that the accused intended to conceal the exact cause of death and nature of the injuries: R v Moffit, 2015 ONCA 412 at para 48
The inference is appropriate where the accused took extreme steps to conceal the injuries, such as cremating the body. The inference is less appropriate where the accused merely buries the body - which is equally consistent with a mere intention to hide the body than to conceal the extent of injuries: R v Moffit, 2015 ONCA 412 at para 49
See Example: R v. Hill, 2015 ONCA 616, at paras 51-62