A bully with incredibly poor judgement. Even if the child was guilty as sin, the principal's actions were still stupid.
But the principal has civil service protection and a union to back her. I am glad it is not my child; I'd be the one in jail, I fear.
Ask my two Son's.
They will tell you in a heartbeat what their mom would have done.
I raised them by myself, now 45 & 50.
I raised HELL many times in many places to take a stand for them.