The nice neighborhood vs. bad neighborhood, only need a 'nice little gun as 5 is enough' vs. gear up for war in the bad neighborhood mantras are vitiated by cases like this. If the it was a workplace 'avenger' (as I've seen the term used), workplaces can go bad in any area. Spousal, partner revenge can happen anywhere.
Speaking to the choir here, hope I never become one of Tom's students in his reports.