To get him slapped, you only have to prove that he followed you to a thread. That’s an easy thing to do by determining who posted to the thread first. If it happens on 2 separate threads and you posted first, you can prove stalking. Unless the poster is bringing a subject from another thread onto a new thread, then it doesn’t matter, that’s stalking.
Its all right here for the mods to witness. And if your criteria is true, then its an easy thing to prove.