Killing Moon  (Paperback, Jo Nesbo)

When a body is found in the forest, the police make a horrifying discovery: her scalp has been removed and sewn back on. But they have no idea why. With a second woman reported missing, detectives fear their worst nightmare has come true. A serial killer is stalking the streets of Oslo. With time running out to find the woman, former detective Harry Hole is called in to think like a murderer thinks... and to track down this killer before they strike again. But Harry has ulterior motives for wanting to solve this case and, if he fails, there could be more than one life at risk.