La défense d'enquête policière inadéquate

R v Malley, 2017 ABCA 186

Lien vers la décision

[50]           The accused may lead evidence to suggest that investigators had tunnel vision, failed to pursue important lines of inquiry, or otherwise carried out a deficient investigation. This strategy runs the risk of derailing the trial process:

... [W]e must remain aware that this defence has the potential to divert criminal trials into blind alleys or to introduce side issues that may prove irrelevant to the central issue of the guilt or innocence of the accused.

(R v Van, 2009 SCC 22 at para 46, [2009] 1 SCR 716)

[51]           Raising the spectre of an inadequate investigation also comes with risks to the accused. In response to a claim of inadequate investigation, the Crown may seek to introduce evidence that would be otherwise inadmissible, including “investigative hearsay” or opinion evidence from police officers: Mallory at para 87. The jury might learn about the accused’s prior bad acts, the results of polygraph tests, or information received from confidential informants. The serious prejudicial impact of this evidence is obvious, even when the trial judge cautions the jury about the limited ways the evidence may be used.

[52]           If the accused impugns the police investigation, the Crown is entitled to a fair opportunity to respond: Dhillon at para 46; R v Candir, 2009 ONCA 915 at para 145, 250 CCC (3d) 139. Any rebuttal evidence should relate to the aspects of the investigation the accused has impugned, however. The opportunity to call rebuttal evidence is not an invitation to sully the accused’s character generally: Dhillon at para 46; Mallory at para 98. The trial judge must also consider whether the prejudicial effect of the rebuttal evidence exceeds its probative value: Dhillon at para 46; Candir at para 146.

[53]           Although courts sometimes refer to the “defence” of inadequate investigation, this nomenclature is misleading. It suggests the Crown must establish that the police conducted a proper investigation in order to meet its burden of proof. Merely suggesting that if the police had conducted their investigation differently some exculpatory evidence might have turned up is, without more, pure speculation. Reasonable doubt must be rooted in the evidence or the lack of evidence, not speculation. A deficient investigation may sometimes influence whether the trier of fact has a reasonable doubt, but the trier of fact should focus on the quality of the evidence, not the quality of the police investigation.