Her family, on nancy grace, stated there was no communication between the two on her computer. That doesn't mean he wasn't following her on any SM sites though.
He could have easily used any of his cellphones to follow her and to use a fake OL personality. I suspect he is on the askdotfm account both commenting and asking questions. Just because there is no record of his name associated with her followers, friends or an anonymous commenter does not mean he didn't have an elaborate OL Personality.