Great suggestions for contacting the local police force, but let's not forget the most obvious and common ones:
Talk to the neighbors! If you do end up buying a home in a specific neighborhood, you will be living there for some time, so why not meet the neighbors before you buy? That way, if you find something totally objectionable, you can save yourself a lot of grief and not even buy a home there. When you do talk to them, you can also get thier veiw and opinion of the overall safety of the area.
The other way is to drive the neighborhood, on different days, at different times. I especially like going by on a Friday or Saturday night.
Associate Broker, CRS, GRI
Keller Williams Southern Arizona