I need to do some homework on this, not your typical street stuff, but I was thinking along the lines of computer trespass laws but the catch is tracking down the offending party and letting them know they are not welcome. Without a court order an ISP would never reveal who is at a particular IP. But there would have to be a subsequent violation after being booted out. I think. I have a call into one of my pals who does computer kiddie porn investigations. He'll have some insight. I'm inclined to think there's some Federal statutes covering these types of matters.
Thank you for your input. Is there a LEO pinglist or other LEOs I can contact?