Investigating a killer who decapitates his victims challenges FBI special agent Maggie O'Dell in Alex Kava's A Necessary Evil. Her mentor, psychologist Gwen Patterson, has her own suspicions about the case, suspicions that circle around one of her patients. When Maggie is assigned to another tough case, the flight from D.C. to Omaha takes her from murdered Jane Does to trailing a possible serial killer of priests. Investigating the murder of Monsignor O'Sullivan brings her into the world of Vatican dealings with the scandals of pedophile priests. Maggie is also brought face-to-face with her old love, Nick Morelli, and the unfinished past between them. Now a district attorney, his good friend is a priest with his own secrets to keep. As the investigation deepens, the web spun by a mysterious Game Master draws in family members and brings from hiding a villain from Maggie's past. Kava proves her mastery of the thriller as she adroitly draws seemingly disparate threads together in a tautly woven fabric of intrigues.