If I were you I would call the police and tell them the situation, ask them for advice on the best and safest routes you can take to protect yourself and your privacy.
If the man has contact again...let him know that you have talked to the authorities, and if he doesnt stop all communication both known and unknown with you you will press chanrges and he will end up in jail for many years... (thats not totally true... but It could get him scared enough to back off)
Have friends stay with you..and save every e-mail or letter he sends so you can show them to the police.....