Hey, Don't worry, you did the best possible thing you could do by not telling him your address and phone number. I think to be honest your friend is in the most amount of danger seeing as she told him where she lived...and if he does come to your house and you feel threatened call the police.
Internet Safety Warning:
Never share your full name, credit card information, school name or location, home address, social security number, phone number, or other personally identifying information through the LiveWire Peer Support Network or any other Internet medium. Doing so can put you in personal danger, and can cause you to fall victim to identity theft or financial fraud.
Its a warning in place for a reason, and thats to stop things like this happening! Don't panic though, instead you need to think about this properly. Is there actually any evidence to label him as someone who has raped girls, slashed tires.. ect. because if there is obviously I'm going to tell you straight away to go to the police and report everything you know. If there isn't though, and its just gossip (which honestly is what alot of teens do these days) then you have nothing on him.. don't bother involving the police. Just tell your parents about him, let them know what you think he has done, and that he is "in love" with you.
Then you need to tell your friend to tell her parents the same thing.. that she has given this guy her address. Telling your parents isn't intended to freak them out but inform them about whats happening. Say you get abducted, and the police go to your parents house and start asking them questions whether or not they know anything? If they know about this at least they can then alert them to this guy. Its all about your personal safety.
Other than telling your parents though there really isn't much else you can do.. maybe just cut contact with him.. make excuses that your net will be down for a few weeks and cut the contact with him. I'm sure he'll soon disappear. Put it down to a bad life experience which we all go through in order to learn from the mistakes we make.
Good luck, I hope this has helped you! Remember, if you need to talk about anything else at all even if its in a week from now I'm always around and about - so drop me a message and we'll chat. Best of luck!
-subway