I would have liked to give this 3.5 stars, but since I can't, I'll go with one up rather than one down. I mostly like the twist ending, though it skates very close to being a bit *too* much of a twist, and as a result is, to me, a bit disappointing -- it comes very close to being over the top, and when I read the end I felt vaguely cheated. However, given the circumstances it's also very appropriate. This is a literate thriller, the suspense is real and pushes the reader along, but it does drag a bit in the middle.
There are also one or two issues that I thought were mentioned/resolved that are then ignored later in the book - I know this is vague; I suppose I could hide the review. Okay. So there was one point when I could have sworn that the students determined Elizabeth was Deanna Ward, and then that plot is ignored.
The set-up is great, and Lavender does an excellent job of creating a very creepy atmosphere. I don't know if this is a book to be re-read, because a lot of the fun is in the puzzle but it is definitely one I would recommend