Whatever his race, knocking on a door as a prank isn't that big a crime. I remember when kids would toilet paper yards, wax windows. My dad's generation did pranks as teenagers, my grandfather was involved in some ----way worse ones than knocking on a door.
I guess when crime was less a problem, people weren't so jumpy, people didn't used to be so afraid of a knock on their front door. It's sad because kids are still kids but now it's dangerous to do things they always have.