A trier-of fact may draw reasonable factual inferences from the post-offence conduct of an accused.
As with any kind of circumstantial evidence, the inferences to be drawn from post-offence conduct will depend on the nature of the conduct, the fact that is sought to be inferred from that conduct, the position of the parties, and the totality of the evidence. Inference drawing is situation-specific and is not amenable to a set of preset rules that categorize certain kinds of post-offence conduct as always relevant to, or never relevant to, a particular fact in issue.
R. v. Figueroa, 2008 ONCA 106, 232 C.C.C. (3d) 51 at para. 33:
Evidence of an accused’s words and conduct after a crime has been committed may provide circumstantial evidence of an accused’s complicity in that offence. The inference involved looks backwards from the later words or conduct to the alleged conduct said to constitute the crime.
No special rule applies to evidence of post-offence words or conduct: R. v. White, 2001 SCC 13 (CanLII), 267 C.C.C. (3d) 453, at paras. 38, 105 and 137, although case-specific instructions may be required where the relevance of the evidence on a particular issue is not readily apparent and the natural inclinations of the jury might lead it astray: R. v. Rodgerson, 2015 SCC 38 (CanLII),  2 S.C.R. 760, at para. 34.
Lies as Post-Offence Conduct
The distinction between out-of-court exculpatory statements that are disbelieved and those that are concocted/fabricated
Among the items of evidence that may be relied upon as evidence of post-offence conduct is evidence of out-of-court lies told by an accused. But the law is careful to distinguish between out-of-court exculpatory statements, such as those that reveal an alibi, which are disbelieved, thus rejected by the trier of fact, and those that the trier of fact finds are concocted or fabricated:
R. v. O’Connor (2002), 2002 CanLII 3540 (ON CA), 170 C.C.C. (3d) 365 (Ont. C.A.), at para. 17; R. v. Coutts (1998), 1998 CanLII 4212 (ON CA), 126 C.C.C. (3d) 545 (Ont. C.A.), at para. 15, leave to appeal to SCC refused,  S.C.C.A. No. 450.
This distinction takes cognizance of the burden of proof and helps ensure that the trier of fact properly applies the burden of proof where the statements of an accused are tendered in evidence: O’Connor, at para. 19.
In many cases, an inference of fabrication will follow logically from mere disbelief of an accused’s exculpatory statements. But the policy that underpins the distinction between disbelief and fabrication militates against using disbelief to infer fabrication. A finding of fabrication must be rooted in evidence that is independent from the evidence that contradicts or discredits the accused’s version of events: O’Connor, at para. 21; Coutts, at para. 15.
The independent evidence relied upon to establish fabrication often originates in sources external to the allegedly fabricated statement. For example, soliciting false testimony from a witness about an accused’s whereabouts at a material time.
But the necessary independent evidence may also emerge from the circumstances in which a false statement is made. Those circumstances, for example the detail provided and the timing of the statement, may reveal an intent to mislead the police or to deflect suspicion and thus may be evidence of a conscious mind that the accused committed the offence charged: O’Connor, at paras. 26 and 31.
Evidence that supports the case for the Crown, which if accepted would cause rejection of the accused’s statement as unworthy of belief, is not evidence of concoction: Hall, at para. 164; Coutts, at para. 16.
Contradictory exculpatory statements of an accused both (or all) of which cannot be true may also constitute independent evidence of fabrication:
R. v. Andrade (1985), 18 C.C.C. (3d) 41 (Ont. C.A.), at paras. 82-83; Hubin v. The King, 1927 CanLII 79 (SCC),  S.C.R. 442, at pp. 445-446; R. v. Samuels (2005), 2005 CanLII 15700 (ON CA), 196 C.C.C. (3d) 403 (Ont. C.A.) at para. 37, leave to appeal refused,  S.C.C.A. No. 313.
See R. v. Shafia, 2016 ONCA 812 (CanLII).