Hi Edder,
 
I can understand why you feel anxious about this situation. It does seem a bit like a criminal investigation - given the surveillance video and the involvement of the "campus cop". But since it wasn't actually a criminal investigation, and since your son wasn't charged with anything, I think it was within the principal's right to speak to your son in the office without you. I'm sure it was scary for him, and for you, to learn that the campus security officer was involved but if they actually thought your son was throwing rocks at a house, then having the security officer there was the right decision. If it really was just a fun joke between two friends, and the cupcake recipient said the same thing, the meeting was probably over pretty quickly with no punishments given.
 
If that's what happened and you're still feeling upset, you should ask to have a meeting with the principal to talk about the situation. But make sure when you go to the meeting you're ready to talk AND listen. You can let the principal know that you were surprised you weren't present for the meeting and ask what the policy is about bringing parents in for those situations. If you go to the meeting with questions, and not accusations, you'll have a better chance of moving forward in a productive relationship with the school and being in a better position to advocate for you son.
 
Good luck!
 
Kat