Pregnant women play key roles in this bone-chilling fourth novel in Gerritsen's edgy, suspenseful series of thrillers featuring Boston Medical Examiner Maura Isles and Homicide Detective Jane Rizzoli. Both of the usually gritty crime fighters are uncharacteristically vulnerable. Rizzoli is carrying her first child, and Isles-divorced and alone at age 40 and suddenly, unsettlingly aware of her biological clock-is experiencing decidedly unspiritual feelings for her priest. As the novel begins, Isles-an adopted child who never knew the identity of her birth parents-is confronted by the corpse of a murdered woman who is apparently her identical twin. Another detective, Rick Ballard, comes forward to say that he knew the victim and is certain her killer is a powerful pharmaceutical baron known...