The Witch Squad Book #1 by M.Z. Andrews

    Mercy is sent to a special school for people like her.  You see Mercy is a Witch and doesn't like it.  She has a hyper roommate named Jax and soon is making friends with other students at the school.  The first week of school there is a murder of a local girl.  They start investigating and also get into some trouble along the way.  They soon realize that someone took the body and Jax to try to put Jax's soul in the body.  They also realize that someone in town is not who they seem.  I really liked this book and can hardly wait to read the rest of the series.