An Ontario Judge recently addressed the duty of Crown Counsel to call witnesses in criminal proceedings. In her 2016 decision in Hillis, Justice Pomerance of the Superior Court determined that the duty to call material witnesses is part of the Crown's litigation tactics, not part of prosecutorial discretion and is therefore reviewable as part of the Court's trial management authority. This decision is an important precedent that clarifies an existing ambiguity in the obligations of Crown Counsel in criminal proceedings.
Based on precedent, eg Krieger (SCC 2002) & Anderson (SCC 2014), it was reasonably clear that exercises of prosecutorial discretion, in bad faith or for an improper purpose, were subject to scrutiny as an abuse of process. However, the scope and limits of the duty to call witnesses, and how it fit into the prosecution role, was somewhat uncertain based on existing Canadian law.
On the one hand, all Crown Counsel were required act in accordance with their longstanding public duties as 'mini-Ministers of Justice' to call credible material witnesses, Boucher (SCC 1954). On the other hand, the Supreme Court's reasoning in other cases suggested that the Crown was still expected to act adversarially, and that there was no duty to call any specific witness, Cook (SCC 1997).
The potential inconsistency between these two positions seemed to a large extent to turn on the determination of 'materiality'. In this respect, early assessments about credibility and materiality of witnesses by the defence and prosecution would depend on alternate 'theories of the case'. In any contested criminal proceedings, both the Crown and the defence are likely to have different theories, the substance of which would usually be in opposition. However, the ultimate determination of materiality and credibility always remains uncertain, at least until the judicial official renders their judgment, accepting and rejecting certain evidence.
I have heard it said that some Crowns might not call a witness or witnesses because the prospective evidence did not advance the prosecution theory of what happened. I have always thought that such a position seemed inconsistent with the public duty of Crown Counsel, to act fairly in their pursuit of justice. Moreover, such a view did not seem to appropriately account for the role of the judge, as the ultimate trier of fact and law.
The recent decision clarifies that exercises of prosecutorial discretion may still be subject to review on the narrower 'abuse of process' standard. However, Justice Pomerance also found that the Crown decision to call, or not to call certain witnesses, is an aspect of the Crown's litigation tactics and is subject to scrutiny by the Court on a wider standard of fairness (paras 41 - 45). In this case, the Judge remedied the potential unfairness by requiring the Crown to call the witnesses directly.
The determination that Crown Counsel must also act fairly in calling witnesses in criminal proceedings is a welcome clarification of the law in this area. This finding also reinforces the balanced role played by all Crown Counsel, to act adversarially in the public interest, but also to assist the Court in finding the truth.