Chief Medical Examiner Kay Scarpetta plays a tense cat-and-mouse game with a serial killer, an old enemy, in her sixth outing (following The Body Farm), and he has her badly rattled. The story begins as a rotten Christmas for Scarpetta: Temple Gault has struck again, leaving a naked, apparently homeless girl shot in Central Park on Christmas Eve; Scarpetta, as the FBI's consulting pathologist, is called in. Later, a transit cop is found shot in a subway tunnel, and, back home in Richmond, Va., the body of a crooked local sheriff is delivered to Scarpetta's own morgue by the elusive, brilliant Gault. The normally unflappable Scarpetta finds herself hyperventilating and nearly shooting her own niece. In the end, some ingenious forensic detective work and a visit to the killer's agonized family set up a high-tech climax back in the New York subway, which Gault treats as the Phantom of the Opera did the sewers of Paris. There's something faintly unconvincing about Gault (in a competitive field, it's tough to create a really horrific serial killer), and Scarpetta, stuck with her own family troubles and involved in a rather glum affair with a colleague, seems to be running low on energy.