My wife and daughter read this a year or so ago, and I picked it up over Christmas. It has a compelling beginning: the first chapter plunges you straight into the mind of the killer, while the second one follows one of the victims on her way to her death. After that, there's a variety of different characters and storylines, only some of which are tied in to the tale of the police's attempts to catch the murderer. The characters are for the most part well-realised and believable, although occasionally the touch of the author falters: at one point, a 'hard-hitting journalist' goes home to "the barn conversion she shared with her lover, county rugby captain Jon Blixen" (p285). Since Jon Blixen doesn't appear anywhere else in the story (and the journalist herself is only in the book for a couple of chapters), this reads like the sort of hastily cobbled-together, slapdash writing that you'd expect in something as bad as a Dan Brown novel.
As others have commented, the supposed hero ('enigmatic detective' Simon Serrailler) is kept so far in the background of this story that I was even beginning to wonder if he was going to turn out to be the killer. Certainly, the way he's only sketched in makes it a little difficult to believe the instantaneous attraction felt by the heroine, 'compassionate, inquisitive, pretty' Freya Graffham. This part of the story seems as if it's been transplanted from another book, and I think it's something of a distraction from the most interesting element - namely, the attempt to analyse and portray the motives of a serial killer in a plausible fashion. Since it's hard for us to understand why anyone would think that killing lots of people would be a good idea, this is a challenging task, but the author makes a good attempt; if it's ultimately unsuccessful, I think it's because of the difficulties in keeping the other strands of the tale moving forward at the same time.