"Christians" on a mission to convert remind of the zombies in Night of the Living Dead. As the sheriff in that movie said: "If you have a gun, shoot 'em in the head. That's a sure way to kill 'em. If you don't, get yourself a club or a torch. Beat 'em or burn 'em. They go up pretty easy."

I am pretty sure that would work on Lubben and her ilk.