posts any danger to the community. The kid was no suspect before the interaction with Wilson. You can always apprehend him later. However, there was no way that Wilson would have let him go, not after he was punched and humiliated by Brown.

Don't overestimate the character of ordinary policemen. They can and will get carried away under tough situations.

You always have to balance the risk of letting someone go and risk of unintended harm. For example, Cleveland police have now implemented more strict rule on whether to chase a car, after the infamous fatal car-chase incident.