Drop in Crime rates

A Policeofficial is attributing a decline in certain types of crime last year to the county's crackdown on illegal immigrants.
A study released last week says homicides declined by 44% from 2006 to 2007. The incidence of rape fell 33%, robberies declined 23%, and aggravated assaults declined 18%.
County board Chairman Corey Stewart says the decrease is due to the resolutions cracking down on illegal immigrants in the county."
As I recall, the main change likely to affect the crime rates, was going after those who presented fake ID, no valid insurance or licenses, etc. This would make not only illegals, but all sorts of other criminals, want get away from the uncommon heat, and on towards the places that are cool for them. Homicides down by a half in one year! This is unheard-of, at least in large jurisdictions like PW Cty., and I believe it has to mean that their policy change got illegals plus a lot of other criminals to move out.