In the Woods by Tana French (2007) Viking

I know a lot of people like this, and it won an Edgar, but to me it's a story that drags.  It could have been told as a short story, but the pages are filled with a whiny-baby detective who can't remember what happened when he was ten years old and had a horrific experience where two friends disappeared forever.  Now he is trying to solve the murder of a ballet prodigy in the same place he grew-up.