Help! Any police experts out there?

The laws differ from state to state, but in MA, here's the gist of it.

To get an HPO (harassment prevention order) or a restraining order (they're very very similar), you need to prove there have been three separate occasions where this person was a threat in some way.

This could be verbal abuse, physical abuse, or stalking would definitely apply here as well.

However, when a child's involved, I don't know if the laws differ. My immediate inclination is to believe that the police would become more involved a lot sooner, especially since this guy sounds like a kidnapper.

If her parents have proof or a witness of the guy with his hand on the girl's arm, that would count as one instance of threatening behavior. If there are other instances of him stalking the house or yelling something at her where there are witnesses or proof, these would count as additional instances.

Again, three of these, and you have your HPO/restraining order. I'd be willing to bet that a parent can obtain one of these on behalf of a child. Check custody battles, I'm sure there are instances of this happening in such situations.

To answer your second question: it would depend. Does a policeman witness this? If so, he'd probably detain the guy for threatening a child. If someone else witnesses this, there may not be much they can do but visit the villian and question him/tell him to cut it out.

Hope this helps!