I agree with LL and most especially with Scully's analysis. Shout it from the rooftops about this creep. Newspapers, TV, radio are good avenues. Stay with the facts as that is what the media will be interested in. Lift up this rock and show the world all the creepy crawlies underneath. The Witnesses care more about image than anything except money. Hit them there and they will not protect this guy.
If this starts to get too big for you emotionally then step back. Be aware that this will trigger intense anger (you may find yourself yelling at the driver ahead of you, or other little things), you may also find your tension level go up.
The best way to combat these negative emotions is to talk about them. As they come up, post about it here, tell friends, neighbors anyone you feel safe with. This is what happened, this is how I feel about it. In that way the poison will not be inside you, but you will release it.