Is this considered !!!!?

My 13 year old son was coerced into having with his girlfriend by another female friend who is also 12 or 13. This girl took my sons clothes off and his girlfriends clothes off and told them both if they didn't do it she would beat the hell out of them both and then stood there and watched them both and told them if they couldn't do it right she would take them to her dad and they could show them how to do it right...Is this a form or and help i don't know what to do. I called the cops and made a report first of all and took my son in for and STD check and called CPS, but school doesn't want to help and im getting no where. My son is now being threatened at school by the girl that forced him to do this.