If you dan't want to post your ideas but still want feedback, feel free to PM me. I'll just post my stuff here for the moment.
what Deadmanwalking and SoulCatcher78 said about missing persons, plus suicides. Children abducted by trolls or the victims of house Raith are unlikely to show up in murder statistics. I've been able to get a look at a crime map of Ottawa's missing persons cases and there are plenty, about 300 in the last 30 days. Even given that most of those people will be found and the causes will be quite mundane in the real world, in the Dresdenverse some of those people may have been taken into the nevernever, or their bodies were disposed of and never found. I haven't been able to track down suicide figures yet; and all I have to go on are the stories from some guys I knew on a rowing team and the number of times they saw bodies first thing in the morning on the canal or Dow's lake, but that may be a biased sample.
The low rate of violent death in Ottawa makes it unlikely we have any numbers of Black court vampires or ghouls around, but that leaves a lot of options. There is a fair amount of variation in the styles of various Red court vampires; Bianca left a trail of bodies, while Ortega was very controlled in the matter of feeding. He kept deaths to a minimum and kept a captive community for his vassals to feed on. If the city does have Reds they probably act in a similar way, confining their feeding to poorer areas of the city (Vanier? Hintonburg?) and using cash and threats to buy the silence of their blood supply. Or if you prefer a darker route, and don't mind borrowing from White Wolf, they may have simply grabbed people no one would miss and keep them caged like battery hens someplace secret; maybe someplace outside of town off a side-road. The Raith don't have to go to those lengths, their feeding is usually non-lethal and when they do kill it probably doesn't look like murder.
One thing I can say is that if this city had a supernatural presence, they would not be sloppy. Ortega or Lara could survive here, Mavra or Bianca would likely cause too much disruption and draw too much notice. Subtler actors and manipulators would find it easier to move about here, provided they were careful enough in cleaning up after themselves.
As far as a element of conflict goes, Ottawa weather suggests we may be a battleground for the Winter and Summer courts. I doubt either of them is responsible for hushing up the fallout of those battles, besides weird and unseasonal heat waves and cold snaps, but that still leaves plenty of options for string-pullers. A government organization could be a potential candidate there, but given powers of the vampires and the sidhe I find it unlikely that such a group could remain [1] hidden, and [2] uncorrupted.