OMG. That is creepy. I would not blame yourself in ANY way for HIS weird behavior. I always say "The only persons actions you can control, are your own."

You did the right thing by telling people and letting him know he crossed the line. Always trust your instincts, they are usually right. I am sorry you have to deal with this. I wish I could offer better advice.

I would report him to the cops so, at least it is on record.
Take all the IM's etc and see what they have to say. Hopefully they can help.