The movie is very, very different than the book. No I'm not talking about just shifting the location, the murders themselves are done differently, with different victims, different motives, and different murderers. The clues have been different as well. The number of characters are reduced, new characters are introduced, and some old characters are either omitted or several characters are merged together at times. The characters have same names but different personalities than the book. A ghost is introduced for no reason, there are supernatural motifs all along.
Hated it, but probably because I had higher expectations. Might be okay for someone who hasn't read the book.