Dans le processus de recherche de la vérité, l’importance de faire ressortir les déclarations incompatibles d’un témoin relève d’un truisme

M.D. c. R., 2022 QCCA 915

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[65]      Dans le processus de recherche de la vérité, l’importance de faire ressortir les déclarations incompatibles d’un témoin relève d’un truisme qui n’exige pas un long développement[5], mais qui mérite d’être néanmoins réitéré dans le contexte de ce pourvoi. En effet, le droit constitutionnel de l’accusé de présenter une preuve est en cause.

[66]      Dans son ouvrage The Law of Witnesses and Evidence, le professeur Sankoff met en exergue le caractère crucial de la mise en lumière des contradictions d’un témoin et l’équité qui doit entourer cet exercice :

The second occasion when independent evidence may be introduced for the purpose of attacking an opposing witness's credibility is when it involves the use of a prior inconsistent statement. As discussed earlier, a prior consistent statement only shows consistency and, generally speaking, is irrelevant since a witness can consistently lie as well as consistently tell the truth. However, a prior inconsistent statement has a totally different relevance. If it can be shown that the witness is saying one thing now and something different on a previous occasion, then, in the absence of a credible explanation for the discrepancy, that witness must be lying or at least mistaken, either now, or on the prior occasion. In any event, it is not difficult for the trier of fact in such a situation to draw the inference that the witness is not reliable and is therefore less credible.

Prior inconsistent statements can be incredibly useful tools of impeachment, and are part of every litigator's toolkit. As the Ontario Court of Appeal noted in R. v. Calder, the use of this evidence is valuable to the trial process, because “[s]elf-contradiction through proof of a prior inconsistent statement can have a powerful impact on credibility both as it relates to the specific inconsistency and the overall veracity and reliability of a witness”.

Still, one cannot automatically assume that a witness who does not state on the witness stand precisely what he or she has stated on a previous occasion is not worthy of being believed. The previous statement may not, in fact be inconsistent; it may merely be expressed differently or with a particular emphasis. Or the witness may be perfectly honest but might have forgotten something, and need his or her memory jogged in order to recall the true facts. The law in this area is designed to permit the introduction of contradictory evidence where necessary while simultaneously ensuring that witnesses are treated fairly and permitted the opportunity to refute the allegation that their in-court testimony is not credible, for one reason or another.[6]

[Renvois omis]

[75]      Le contre-interrogatoire doit être équitable envers le témoin qui aurait prononcé des déclarations antérieures incompatibles avec le témoignage rendu lors du procès : le témoin doit pouvoir s’expliquer[11].