Bullies have a distinct advantage when they enter a church. That's because his or her targets, as well as nearly everyone else, assume all fellow parishioners have good intentions. So it often takes a long time to catch on to the fact a disordered person is in your midst.
One sign there are one or more sowers of discord is that people who once worked well together no longer do. Sometimes there will be a scapegoat. The bully typically has a cadre of allies, or else he or she wouldn't have the power to disrupt. However, it's very difficult to figure out who's really behind all the commotion. That's because narcissists are extremely clever. They may have manipulated a proxy into doing their dirty work.
It's hard to even fathom that such a deceiver could operate in a religious setting, because, as Christians, we're supposed to assume the best, and view our neighbor in a positive light. But Our Lord warned us against these wolves. He also told us to be "wise as serpents and simple as doves." (Douay-Rheims version.)
Flickr photo by arranET