True Evil

"At the center of the mystery lies a maddeningly simple question: If these people really were murdered, why can't the FBI prove it? Rigorous autopsies have uncovered no forensic evidence of foul play, and the police believe no crimes have occurred. As Dr. Shepard and Agent Morse struggle against an invisible adversary, Shepard realizes that he's working with a desperate woman. The reason: the killer's last known victim was Alex Morse's sister, who from her deathbed accused her husband of murder and extracted a vow that Alex save her ten-year-old nephew from his father. This has driven Alex to risk both her life and her career to fulfill that vow. But Chris Shepard soon feels desperation of his own. As he probes his wife's hidden past, he is confronted by the probability that the woman he loves wants him dead."--BOOK JACKET.