Well, the school got their wish. They got rid of this particular student. This is why some schools will have a small private room where such a child can be taken for a while, until they can quiet themselves down. Meanwhile, classes can continue uninterrupted for the other kids.
Did the mother know about these ‘disruptions’?
Document every thing.
My sister manages such a room. It is a combined tutoring center / calming room for kids having meltdowns and losing control. Most of the time my sister and her colleagues are tutoring, but an incoming basket case has top priority.
It’s a very effective solution.
Calling the police, not calling her parents, putting her in the psych ward for TWO days — I cannot imagine a worse treatment of a young child.