With neck bruises and so on seems to me your state's civil commitment procedure could have been invoked ~ that will provide a hearing, and the cops will come to pick up the target individual BEFORE the hearing.
Somebody there needs to find a lawyer real quick and get cracking on locking up a dangerous party.
You know, it's not just ordinary folks who don't know any of this ~ Mr. Lanza simply abandoned his wife and son ~ he moved out of there to another state after the divorce. But you'd better believe he knew that kid was dangerous. And, he had access to expensive lawyers ~ and he did nothing about the kid.
My mother lived in NJ at the time and the state of NJ insisted on taking everything that her husband owned and selling it at auction before they would take custody of him. Then they put him in a care center and medicated him into a zombie. He died within six months.
My sister went to visit him once and everyone there was the same way, medicated and tranquilized into zombies.