This isn't the horror novel I thought it was going to be and it's not the "straight crime" novel that the blurb on the front claimed it to be. In fact I'm not really sure how
to classify it but maybe I shouldn't worry about it.
There were elements of horror, there's a kind of non supernatural notion of a vampire here, and there are crimes but this doesn't start with the crime and then try to work out who did it, rather it starts with the perpetrator and then tries to find out what it is he did (and why).
The narrative is presented as a psychiatric case file on which you, the reader, are snooping on, with mail correspondence, interview transcripts and essays attached.
Quite an interesting and somewhat different tale by an author known primarily for his science fiction.