Dealing with problematic people in the workplace is an art form.
People who spend their time looking to undermine other employees have the advantage of deniability.
Problematic people usually have a large network of people willing to deny their pity, destructive behaviour because people always protect their own.
My best advice is once the dust is clear to leave an organization that allows people to cause issues without out recourse. Time is short and being in the presence of people out to get you because of their own emotional issues is a waste of time. And besides you already went through that experience in high school.