The only way I think you're going to be able to get it is through the intervention of police agencies, and at least documenting or providing.... They would be the best because they're the ones on the front line, then the prosecution, and I would include race-based statistics. The problem is you're asking people, both the police and the crown attorneys, who already have a significant amount on their plate, to assist with statistical data collection, and that's going to be difficult to do.
I think that's the only way you're going to get that information you need, especially with those who have the intervention of the criminal justice system, whether charges are laid or not.