Bullying

My son received "in school suspension" today for an event that took place last Friday after school.
Evidently, someone accused him of starting a rumor and the person who the rumor was about informed others that he was going to fight my son after school.
At first my son minimized the situation with me on Friday's report. Today was more involved.
Sometimes it's hard to know what to believe. My son is small but has a way of instigating trouble indirectly with comments. However, as I began talking with a parent who witnessed the end of it, it is clear that my son was being bullied at that moment.
And whatever had happened escalated to the level of violence. When I made the police report, they asked some interesting questions one of the first being "Were there any weapons involved?" The second "Was it over a girl?" Fortunately I was able to the best of my knowledge answer "no".
Scary times though. When I think of all that can or has happened in the nation over things like this. The school's response, well the stories are all different so they just suspended everyone involved...at least the main players. (Reminds me of a parenting technique I've employed unsuccessfully.)
Evidently, there has been a conflict between my son and this other boy in class for most of the year. My husband just learned about it in happenstance from one of the teachers. Shouldn't the school contact the parents be contacted early on rather than when it escalates this far?

Shouldn't I have clued in sooner? Looking at now, he's been hinting at problems but afraid to say anything for fear of greater retaliation.

There were over 20 kids watching and one parent who stopped and then drove on. Thankfully, there was one parent who happened upon the scene and was able to split them up.