Just a word to the wise IF you happen to travel to the interior of Mexico. Be very wary of ANY Mexican state police. The federales are untrustworthy enough all by themselves, but the vast majority of state police are themselves part of the cartels.
Remember this when you're riding in a tour or resort bus and you have to stop for a police checkpoint. Those guys in body armor carrying automatic weapons that board the bus and walk through seat by seat, eyeing each passenger are not hunting for criminals!
A buddy was trying to talk me into a motorcycle trip through Mexico.
Me: "Uh.....Canada seems nice."