Another Riot At Vincent H.S., Milwaukee

Another riot broke out at Vincent H.S. in Milwaukee today, injuring 3 police officers and a safety assistant. the fight happened after school in a parking lot. http://www.jsonline.com/news/milwaukee/70667407.html
I have somewhat warm thoughts about Vincent- it is where I started my teaching career after graduating from college.
How can this happen at a school that is in a basically quiet area of Milwaukee? It's not like the school is in the middle of a neighborhood, like the late North or South Division high schools are.
Apparently, the administration and cops and not getting good intelligence from the kids at the school. I know at the school where I teach now, there is good intelligence as to when fights break out and many times we know about a potential fight before it breaks out. And after school surveillance must be lacking at Vincent. To let that big of a crowd gather after school hours just should not happen, especially after other incidents at school. They need to disperse the kids immediately after school. This includes inside and outside of school and it's parking lots. Finally, the kids need to be able to trust it's administration, teachers and school police officers to the point where if a fight is about to break out, the kids feel they can go to these people and report it.
It's just another sad day at Vincent, my first school I taught at.