Silhouettes: An Andy and Gabrielle Amato Mystery

A serial killer is ``whacking out'' Mafia mobsters who are hidden in the federal witness protection program in West Palm Beach. Lately come to the upscale and generally crime-free environs are husband and wife detectives Andy and Gabrielle (Gabe) Amato, who have made their reputation in busy Miami. While Andy, the intuitive partner, believes there is a too carefully planned sameness in these murders, apparently arranged by organized crime, Gabe relies on her computer to point to the source of the crimes. Andy, closing in on the killer of killers, who arranges grisly scenarios for his victims, battles the local law enforcement bureaucracy and the FBI, whose strategies he questions. Making use of old mafioso connections from New York, he inches closer to the unlikely perpetrator and finally cuts a deal to save Gabe, taken hostage in a bloody denouement. Though somewhat derivative, this debut mystery is sexy, tough-talking and entertaining. The author is a lieutenant in the Lake Worth, Fla., police department. (Dec.)