This is toxic behavior. Unless you've heard it from the person's mouth, or read it, you shouldn't treat that person any different. Most of the people you think are out to get you are probably not out to get you. . .not really.
Another symptom of this behavior is you start telling negative stories about this supposed villain just so when you finally confront them you have ammunition. That becomes RIGHT fighting and that's also toxic behavior.
So remember, if you think a person is toxic, check your filters and see what they actually did to you. If it didn't come directly from them, then you may have become the villain in your own story.