Kid the Phantom Thief

So the newbie then decides to plan a revenge scheme with her new friends to plan a prank on the bully, but then the bully is actually murdered, so the girl then is feeling guilty and tries to find out the her ex-friends' murderer, in the end, the murderer was a teacher because the teacher kills witches (The bully was actually a witch). The teacher dies and the girl lives, the end, xD.