The entire mess is unfortunate and should have never happened. Regardless of what the girl did the officer could have handled it better. That's what training is for, especially when you're working around kids.
Also, if the girl was asked to leave the classroom then she should have done so. You can't bank on everyone being patient and putting up with your shit. If you feel they are wrong then go to the office and get your parents involved. That's if she was indeed messing.