Evidence - Motive. R. v. Megill
In R. v. Megill (Ont CA, 2021) the Court of Appeal considers the issue of a witness' motive to testify:
 The motive of a witness to testify is a subject that may be explored in cross-examination. For example, a witness may be cross-examined about circumstances that tend to show bias, interest or corruption. The witness' denials may be contradicted by evidence as an exception to the collateral facts rule: see, for example, Attorney General v. Hitchcock (1847), 1 Ex. 91; McDonald v. The Queen, 1959 CanLII 25 (SCC),  S.C.R. 186, at p. 191; and R. v. S. (A.) (2002), 2002 CanLII 44934 (ON CA), 165 C.C.C. (3d) 426 (Ont. C.A.), at para. 32.. R v McSween
In R v McSween (Ont CA, 2020) the Court of Appeal explains the difference between motive and intent:
 The trial judge also erred in his approach to the mens rea for offences under s. 163.1. The error lay in confusing motive and intent.. R. v. McDonald
 Intent and motive are two distinct concepts. The Supreme Court spoke of the interaction of motive with intention in Lewis v. The Queen, 1979 CanLII 19 (SCC),  2 S.C.R. 821, at p. 831 noting that while often spoken of in the same breath, intent and motive are conceptually distinct. This was again reiterated in in Dynar v. United States, 1997 CanLII 359 (SCC),  2 S.C.R. 462, where Cory and Iacobucci JJ. wrote, at para. 81:
It does not matter to society, in its efforts to secure social peace and order, what an accused's motive was, but only what the accused intended to do. It is no consolation to one whose car has been stolen that the thief stole the car intending to sell it to purchase food for a food bank.See also R. v. Hamilton, 2005 SCC 47,  2 S.C.R. 432, at paras. 38-45; Don Stuart, Canadian Criminal Law – A Treatise, 7th ed. (Toronto: Carswell, 2014), at pp. 244-249.
In this criminal case, R. v. McDonald (Ont CA, 2017), Watt JA stated with respect to motive:
 Motive is not an essential element in murder or in its classification as first degree murder. But evidence of motive is relevant, material and admissible in prosecutions for murder, especially where the case for the Crown is wholly or largely circumstantial: Luciano, at para. 164; R. v. Lewis, 1979 CanLII 19 (SCC),  2 S.C.R. 821, at pp. 833-38.
 Evidence of motive is material because it helps to establish two critical components of the case for the Crown: the identity and state of mind of the person who is alleged to have committed the offence: Luciano, at para. 165; Plomp v. The Queen (1963), 110 C.L.R. 234 (H.C.), at pp. 243, and 249-50; R. v. Griffin, 2009 SCC 28,  2 S.C.R. 42, at paras. 59-60; R. v. Candir, 2009 ONCA 915, 250 C.C.C. (3d) 139, at paras. 51 and 72.
 Evidence of motive is a species of circumstantial evidence used to prove, or to assist in proving, a human act. By nature, evidence of motive is prospectant: because a person had a motive to do an act X, that person probably did the act X alleged: Peter Tillers, ed., Wigmore on Evidence, vol. 1A (Toronto: Little, Brown and Company, 1983) § 51, pp. 1144-1146; see also R. v. Yumnu, 2010 ONCA 637, 260 C.C.C. (3d) 421, at para. 273, affirmed on other grounds, 2012 SCC 73,  3 S.C.R. 777.
 Motive may be evidenced by a person’s words, conduct or some combination of each. On occasion, the conduct said to establish motive may involve the commission of offences other than those charged or other extrinsic misconduct: Luciano, at para. 114. The evidence of extrinsic misconduct [SS: similar fact evidence] must be relevant to prove the alleged motive and properly admissible under the rules of evidence.