Bake, I think the paper you're referring to compared Vancouver BC to Seattle, WA rather than Vancouver, WA (which is MUCH smaller than the Canadian city). IIRC, the gist of the study was that gun violence was much higher in the US than a similarly sized and located Canadian city.
Then someone tore down the demographics, and demonstrated that if the murder rates of the two cities were compared by race, the rate among Orientals was roughly the same, while the rate for Whites was actually lower in the US than in Canada. What skewed the study was that the rates for Blacks and Hispanics were MUCH higher, and there were orders of magnitude more of them in Seattle than in Vancouver, BC.
That may not be what you're referring to, but it was another flawed study published many years ago.