Unwanted, by Kristina Ohlsson

Very good, although I totally had the key to the puzzle figured out about 100 pages in. Still, watching the police team work through a very complex investigation of the kidnapping and subsequent death of a child followed by more mayhem and horror was fun. Plus, Sweden! And a cameo appearance of an American profiler of serial killers, whose description is worth the price of the book even if he's only around for about 6 pages.