I didn't figure out the killer until the end. Even after A.J. pretty much spelled out for Jake who it was and how and why it happened. I still didn't believe her and thought it was someone else.
Andy and Nick were kind of annoying in that their resolution was predictable. If it didn't turn out the way it did, then it would mess up the plot line of A.J. and Jake.
Speaking of A.J. and Jake, I hate to say this, but I was a tad bit disappointed he didn't follow through with what he talked about on his midnight visit to A.J.'s house. That would have been a big shake up and not followed the norm I've been reading in other books. There might be some books out there where what I would have wanted to happen, happens, but I haven't read those yet.