If and when should return to troll or harass again, let it be known that his actions are must not, will not go unpunished. He once asked someone to do a couple of commissions at one point. He wanted to talk to the one that did them for him on Discord, but was refused. That's where the harassment and threats came into play (and also, one on voicemail that was more vocal... and a whole lot creepier). I won't speak of the commissioner's name due to confidentiality, but he needs to know and understand that if he should re-offend, prior to return, he's to end up worse than on report.
And pass the word along.