Now I can understand someone working at a school would be a little concerned if they heard about a conversation in which a girl said "I'm going to shoot you and I will shoot myself." Naturally I'd make sure to ask the girl about it when I saw her. My line of questioning would go along the lines of: "I heard you said you were going shoot somebody at the bus stop this morning. What's that about?" "Pink bubble gun? That shoots bubbles right?" "Well okay then, have a nice day. But from now on try not to say you're going to shoot people. That can scare people who might not know what you're talking about."
What I would NOT do is question a FIVE YEAR OLD GIRL for THREE HOURS, WITHOUT her parents present, suspended her for making a "terroristic threat," and told her parents she needed to be evaluated by a psychiatrist. And if it was my daughter, I wouldn't simply be demanding an apology and an expunged record, I'd be looking for a transfer because there is NO WAY i'd be letting these idiots have anything to do with her education.
I believe in gun control and I believe in taking threats seriously. This however is exactly the type of paranoid hysteria that the far right gun nuts suffer from (And no I do not mean that as a blanket grouping of ALL gun owners). Bullying of any kind is deplorable, and authority figures going out of their way to terrorize a student in such a manor is inexcusable. As I said I wouldn't trust these people with my children, and I sure as hell wouldn't trust them with firearms.