Crime novel doesn't make a case for itself

The Rottweiler, By Ruth Rendell Crown, 339 pp., $25

Ruth Rendell has been increasingly intrigued by the diversity of life in London in her recent crime fiction. In ''Adam and Eve and Pinch Me," from a few years ago, she created a rich panoply of characters walking in and out of each other's lives against the backdrop of Tory hypocrisy and media malfeasance.

Her new book, ''The Rottweiler," follows a similar form. Much like a Robert Altman movie, characters intersect before getting swept up in their own private tempests. Rendell shifts the focus rapidly, though what worked in ''Adam and Eve" does not quite gel here.

''The Rottweiler" takes its name from what those holy terrors on Fleet Street have dubbed a murderer of young women whom the police are helpless to find. It seems that one of the victims had a bite mark on her neck.

Rendell seems fascinated by the new multicultural mix in London, though she is no more sentimental about the new melting pot than she has been about class differences in past novels. Neither money nor poverty buys nobility; nor does skin color.

It's a pity, then, that this collection of folks isn't particularly interesting. The story centers on a building that is part boarding house and part antique shop, to which all the characters have some relation.

And most of the characters are not what they seem. The exotic helper in the shop balances two fiancs, the better to score more jewelry, but she's already married. There's a boarder with a ''variable Russian accent." Inez, who runs the place, retreats to her room to watch videos of her late husband's TV show, which has become preferable to reality. Then there's the double life led by the murderer.

Also in the mix are a mildly retarded young man and his aunt, prompting Inez to ask herself, ''Did that mean you had to . . . well, have learning difficulties before you could be transparently honest?"

Inez and the young man's aunt, Becky, are the only remotely likable people in this mix, but because Rendell is jumping around so much, neither is as developed as her more compelling flawed heroines.

More distressing, the murderer, who is revealed a third of the way into the book, is not as interesting as Rendell's usual homicidal maniacs. He has the insight to psychoanalyze himself, and Rendell has some fun with his fussiness. He prides himself that he could easily kill a non-Caucasian, so he's no racist, and deep down he's really a law and order man. (''Crime in this city outraged him.")

Again, though, the twists in his psyche are not all that fascinating, and the reason for his losing control turns out to be rather run of the mill. Perhaps Rendell is playing off the media frenzy that casts him as a vicious dog, when he's pretty mild-mannered at heart.

As in her other books, Rendell paints an eerie portrait of a world where coincidence and randomness have much to say about who lives and dies, who fails and who thrives. The murderer thinks at one point, referring to himself in the third person, ''He always had liked silence and calm. Look what had happened when, uncharacteristically, he went into a 'nightspot,' a noisier place than anywhere one could think of. If he hadn't, perhaps the cycle of deaths might never have begun."

But the jarring, callous nature of the world Rendell describes does not sweep us into its core. The writing is too diffuse, the characters too undemanding of our attention.

Ed Siegel can be reached at siegel@globe.com.