I'd probably call the police and ask them what to do in this situation. Explain what happened, and see what they recommend. I would also call the church authorities and tell them, and then prepare yourself to find another church, because you guys are going to be the ones who get blackballed. Quite frankly, however, if the church authorities don't take you seriously, why would you want to go to that church?
At least if there's documentation of the incident, two years down the line when this guy loses his cool and goes overboard with a kid, no one from the church can say "Gee, it came out of the blue". Anything you do, do it in writing.