How is this a property managers concern?
Complaints like this need to go to a court of law and get prosecuted by the law, not arbitrated by an apartment complex manager... For one, they aren't even remotely qualified to adjudicate a damned thing, and for another, they have exactly zero authority to implement anything punitive or legally binding.
Take this shit to court, get a restraining order, and have the court mandate that the shitbird can't live in the same complex as the victims. That's the right answer. Expecting an apartment manager to adjudicate and implement punitive measures for this or anything else is absurd... Landlords don't need this sort of authority and I can't imagine why anyone would ever want them to have it. They have quite enough power already...