Early in our careers, officers may get confused by all the different views out there regarding when to arrest if a victim or witness is not forthcoming with a statement. In regards to the arrest, an arresting officer must subjectively have reasonable grounds on which to base the arrest. Those grounds must, in addition, be justifiable from an objective point of view, such that a reasonable person placed in the position of the officer must be able to conclude that there were indeed reasonable grounds for the arrest. On the other hand, the police need not demonstrate anything more than reasonable grounds. Specifically, they are not required to establish a prima facie case for conviction before making the arrest (R. v. Storrey (1990) S.C.J. 12).
Officers may also be concerned with the “Likelihood of Conviction” or some jurisdictional crown policies that utilize a “reasonable prospect of conviction” threshold that require prosecutors to determine that there is a 51% likelihood of conviction before a charge should proceed. This policy is not for the officer to become entangled in. We are an important part of the justice system, as is the crown, defence, judge, witness, and so on, but we each have our roles to fulfill. We do not have alot of control, if any, when the crown decides to withdraw a charge in jurisdictions where police formally charge someone without requiring prior crown approval, or where the crown decides not to proceed with charges in jurisdictions where prior crown approval is required before we lay the Information. The crown has its core policies to adhere to and it is not our function to “act” as the crown when deciding whether or not to arrest someone.
We do need to adhere to our various powers of arrest, limitations to an arrest (e.g. 495(2) CC), and so on, but whether or not we will get a conviction in the end is not a requirement in making the arrest. We do not have to charge everyone we arrest and we do not have to arrest everyone we intend to charge; what we do need is to understand our function in the justice system and remember that we also engage in another important aspect – an investigation. A thorough investigation may result in charges being laid, consultation with the crown, and other avenues, but a prima facie case or “likelihood of conviction” does not equate to reasonable grounds to believe for a lawful arrest and vice versa.