If that were me and my family the first thing I'd do is make sure everyone was carrying at all times.  Then I'd get all of us to the phone store and get all new phones for everyone involved.  Then check your vehicle for any tracker you can find.  There ought to be a way to locate a tracker on a vehicle but I don't know about them.

   The police probably won't get involved until someone is injured or dead and that sounds like a good possibility from the way they are acting so I'd try to make sure it's not one of my family that was the dead one.  It's a lot easier to argue your case alive than it is dead.  Meth heads aren't going to react rationally.