Personnel Director as Serial Bully
I worked in an international HQ and the personnel director (!) was a "serial bully". He had multiple targets, but one head target: the VP of that organisation. As I and some other collegues stood by this VP, we became targets as well.
His actions were insidious and in order to "eliminate" me as a target, he hired two people to do the job for him in a mobbing setting. Once we were elimated he hoped in that way to "eliminate" the boss himself by proving how bad he was by the turnover in personnel!
He did nothing else than trying to get people at each other throats with insinuations, gossip, threats, lies, fabrication to those underneath him in the organisation. At one point the whole HQ was paranoid, but he stayed always in the dark.
I suffered severely from the mobbers at the time, but only realised years later what had happened to me. At the time I had been able to place it back into perspective by a long holiday in India and a new job in another company without mobbers. It feels unethical, immoral and as harrasment and so it is. I lost all my friends of that time, but now, years later, I reconnected with them, as I believe that the mobbers should never win!