R. v. Youvarajah 2013 SCC 41:
B. Admissibility of Prior Inconsistent Statements
 Historically, an out-of-court prior inconsistent statement of a non-accused witness was admissible only to impeach the credibility of the witness. A prior inconsistent statement — hearsay evidence — was not admissible for the truth of its contents unless the witness adopted the prior statement in court. Otherwise, the jury was limited to rejecting the viva voceevidence of the recanting witness; the jury could not substitute the contents of the out-of-court statement.
 This traditional rule excluding prior inconsistent statements was altered in K.G.B. to conform with the evolving principled approach to hearsay. On an exceptional basis, a prior inconsistent statement is admissible for the truth of its contents, provided the threshold criteria of necessity and reliability are established.
 In K.G.B., at p. 787, Lamer C.J. stated that the focus of the reliability inquiry, when dealing with prior inconsistent statements, "is on the comparative reliability of the prior statement and the testimony offered at trial, and so additional indicia and guarantees of reliability ... must be secured in order to bring the prior statement to a comparable standard of reliability before such statements are admitted as substantive evidence".
 Accordingly, Lamer C.J. held, at pp. 795-96, that a prior inconsistent statement of a non-accused witness may be admitted for the truth of its contents if the so-called K.G.B reliability indicia are met: (1) the statement is made under oath or solemn affirmation after a warning as to possible sanctions if the person is untruthful; (2) the statement is videotaped or recorded in its entirety; and (3) the opposing party has a full opportunity to cross-examine the witness on the statement. Such K.G.B.statements have become prevalent, especially in murder investigations.
 However, theK.G.B. indicia are not the only means of establishing threshold reliability. The prior inconsistent statement's threshold reliability may be established by: (1) the presence of adequate substitutes for testing truth and accuracy (procedural reliability); and (2) sufficient circumstantial guarantees of reliability or an inherent trustworthiness (substantive reliability): Khelawon, at paras. 61-63. These two principal ways of showing threshold reliability are not mutually exclusive: R. v. Devine, 2008 SCC 36,  2 S.C.R. 283, at para. 22.
 The admissibility of hearsay evidence, such as the prior inconsistent statement in this case, is a question of law. Of course, the factual findings that go into that determination are entitled to deference and are not challenged in this case. As well, a trial judge is well placed to assess the hearsay dangers in a particular case and the effectiveness of any safeguards to assist in overcoming them. Thus, absent an error in principle, the trial judge's determination of threshold reliability is entitled to deference: R. v. Couture, 2007 SCC 28,  2 S.C.R. 517, at para. 81.
 To obtain a new trial following an acquittal, the Crown must show that the trial judge erred and that this error "might reasonably be thought ... to have had a material bearing on the acquittal": R. v. Graveline, 2006 SCC 16,  1 S.C.R 609, at para. 14. The Crown is not required to establish "that the verdict would necessarily have been different": Graveline, at para. 14. This is still, however, a "heavy onus" for the Crown: R. v. Briscoe, 2010 SCC 13,  1 S.C.R. 411, at para. 26.