To be honest, I don't know how bullies' systems work in the US or other western countries, but I think everywhere is similar. I will describe some pattern I noticed in bullying and the question is what psychology knows about the reasons of this specific pattern. The pattern is when a bully in the street starts assault on a prey, he starts by conversation, usually, by asking something. And sometimes there is no "right answer" and aim is just to beat the prey. Why the bully doesn't start straightforward from beating the prey? Here, I am not talking about the bullies whose aim just to take money or something valuable, but about the bullies who want to beat the prey despite everything.
In answers, I hope to find some research papers where this question is covered.