Scarpetta: Cruel & unusual

Although I can't put down the Scarpetta books, they are so far following the same formula: Scarpetta is going after a serial killer and find herself threatened by the killer. Unlike the previous books, although Scarpetta and Marino discover the identity of the killer, he manage to run away and is not cuaght. I'm now reading the next book in the series and Scarpetta & co. suspect that he is behind the new murder in that book.