I thought there were vast differences between the characters, and character development in book and movie as well. Dix was a much stranger character in the book for many reasons. His anonymity as writer, antisocial behavior with strange women (stalking) and his habit of practically pretending he had murdered the women all contributed to a much more effective character in the book. The only sign that he was a little “off” in the film was his description of how the murder happened to Brub and his wife. Even then I , like them, didnt cast aside the possibility he was a eccentric person and a passionate writer. In the book I thought that although he was a little more strange (though less angry consistently) the point that he was a determined mystery writer came through in many instances. He put himself in the place of the murderer trying to understand what it feels like to be hunted and to want to murder another human being, even at the risk of being suspected himself.
I also thought the book, possibly because it was written by a woman, showed its female characters as stronger and more developed than the film. In the book Sylvia mentioned she was a psychologist and did not receive the same criticism as in the film where Brub showed a major insecurity, being threatened by her education. Also, Gray was a much more sexually and emotionally strong character than in the film. In the film she almost immediately turned domestic upon agreeing to date Dix, while in the book she was the kind of girl who threatened to literally break his balls if he didn’t take his hands off her, and believably. She was a much more fascinating character because of elements only the book expressed.
The idea of domestic and sexual violence was much more prominent in the book than the film. Dix was obviously controlling in the film but his mental immersion in the strangler cases, only showed when he considered strangling her at the end. The development of this passion was only shown in the film through random bouts of anger and the “how it happened” incident but not as fully as in the film with his inner dialogue, almost pretending to be the killer. I agree with Thekla that the loneliness, this inner world, self fulfilling prophecy, antisocial behavior was only really expressed in the book. The film was good but after reading the book I feel so much was lost in it.