In this follow-up to her debut, Tunnels, Gagnon delivers another psychological crime thriller again featuring FBI special agent Kelly Jones, who closely resembles Clarice Starling, Thomas Harris's heroine in Silence of the Lambs. This time, Kelly investigates a string of grisly crime scenes left in the wake of a sadistic serial murderer's frenzied path along the northern stretch of the Appalachian Trail in Vermont and Massachusetts. Gagnon's plot is fast-paced, appropriately detailed in its forensic depictions, and reveals an attention to authentic FBI detection procedures that lets the reader know that the author has done her homework. An engaging and quick read. Recommended for popular fiction collections for readers who like Jeffery Deaver, J.D. Robb, and Kay Hooper.