The decomposed bodies of Fred Cheyney and Deborah Harvey don't show up for months, well into Dr. Kay Scarpetta's account of her investigation into their disappearance. The two lovers are the fifth pair in a string of mysterious ``couple murders,'' all bearing the same characteristics: two young people completely vanish, leaving behind an abandoned car and no clues about their fate. Months later the skeletal remains are found by hunters in remote wooded locales, and no evidence about the causes of death can be discovered. At the same time, the FBI appears to be foiling attempts to discover the identity of the murderer by withholding crime-scene information, and Kay's old friend Abby, a newspaper reporter, complicates matters by conducting her own search for the truth. This rich brew makes for a compelling story to which Cornwell has added such stand-bys from her two previous Scarpetta novels as Pete Marino, a middle-aged police detective, and Benton Wesley, an FBI investigator who knows how to keep a secret.