Had a pretty good conversation with a former Associate Principal at whatever Waterloo high school is the "dangerous" school.
What it boils down to, he said, is that at one time, Waterloo was the farthest one way train stop people from Chicago could get to. So, if you're slinging drugs or running from the cops, Waterloo was where they went.
Obviously, times have changed, but a lot of people have stayed. As time goes on, those genes are eventually erased. So, in his opinion, Waterloo has become a much safer place the last couple decades, but still has the bad apples that ended up in the area.