Scratched Off — Julie C. Gilbert

Failure means more people die. The Big One could make Sam's career or ... break him.FBI Special Agent Samuel Kerman has been tasked to catch a wildly erratic serial killer dropping bodies in Pennsylvania state parks. The victims differ, and the manner of murder changes every time. Amid the mountains of physical evidence, only a mysterious gray dust and declarations of guilt or innocence link the crimes.It's not much to work with, and the case drags on for months. Then, things go from bad to worse when the killer makes it personal. Family, friends, strangers ... everybody's in danger of being scratched off.