my thought is that her father was killed by a vampire right in front of her when she was a child, which gave her this desire to get vengeance for his death. so for years she's been putting tracing spells on her suspects and trying to rid portland of all vampires once and for all. obviously one witch isn't going to make a dent and she's playing with fire all the time because she isn't trained whatsoever but her intentions are in the right place (in her own mind.) she has yet to actually kill anyone but she's done her fair share of trying.