R. v. Khela, 2009 SCC 4
Click here [1] to link to the full judgment.
(Criminal / Jury charge)
The accused were convicted of first degree murder.  They appealed, arguing that the trial judge had failed to provide a sufficient warning to the jury about using unsavoury witness testimony.  The Court dismissed the appeal, holding that a so-called Vetrovec caution must: 1) draw the jury's attention to the evidence requiring special scrutiny; 2) explain why this evidence requires special scrutiny; 3) caution the jury that it is dangerous to convict on unconfirmed evidence of this sort, though the jury may do so if satisfied that the evidence is true; and 4) that in determining whether the evidence is true, the jury should look for evidence from another source which indicates that the unsavoury witness was telling the truth.  The Court also indicated that there is no single formula for a proper caution.
Majority/Concurring: 6/1