I would never have called in a cop. Tell the girl to go to the office and, if she's unwilling to behave, expel her until she's ready.
That the administration called in a cop shows what a failure they were.
ROTFLMAO.
Totally absurd. They told her to go to the office, both her teacher and the asst principal. She wouldn't. So now your plan is for someone to pronounce over her, "You are hereby expelled", which would have accomplished what? Then she would have complied, put away her cell phone, and gone home? Great plan there, outstanding, first rate.
Your stubbornness and unwillingness to face the facts makes discussion of this with you pointless and shows this to be true beyond measure: "these "kids"...are showing more sense and a more correct assessment of this incident than you ever have or will."