The late, great champion of civil and women's rights, Dianne Martin, agreed

The late, Dianne Martin of Osgoode Hall Law School was a staunch advocate for justice in the criminal justice system and, particularly, for women, who are still (as I have been) disregarded by the legal system. She stated, referring to appropriate rules, laws and legal inquiries that govern police behaviour:

“it is important to remember the limits of an analysis of legal rules and interventions. Two are particularly important. First, for police, the law is not a barrier or a threat, it is their "tool", and they have considerable expertise in wielding it in their own interest. Secondly, the extent to which police control the ‘facts’ of an incident and the way that those 'facts' are interpreted will in most cases be unchallenged and will often determine both the ultimate outcome and the public's perception of what happened and why. In that sense the ‘facts’ matter more than the rules, and processes which determine how evidence is gathered and shaped, and how it is analyzed are every bit if not more important in achieving accountability and transparency than the most elaborate set of substantive rules.” [my emphasis]

From: Martin, Dianne. "Accountability Mechanisms: Legal Sites of Executive-Police Relations – Core Principles in a Canadian Context". Police and Government Relations: Who's Calling the Shots?, edited by Margaret E. Beare and Tonita Murray, Toronto: University of Toronto Press, 2016, pp. 257-312. https://doi.org/ 10.3138/9781442684690-009