Principal was advised, he actually came out and "patrolled" the area.  He was out same day as we had the police out.  He also had warned students there would be unmarked police cars around.  helped for that 1 day.  Students knew his car, even have had some ask me if he lived at my home because they saw his car in my drive. 

only answer i see is constant patrol by the neighbors...kids lack in "home training".