On June 25, 1973, a seven-year-old girl went missing from the Montana campground where her family was vacationing. Somebody had slit open the back of their tent and snatched her from under their noses. None of them saw or heard anything. Susie Jaeger had vanished into thin air, plucked by a shadow.

“ShadowMan,” by Ron Franscell, is a pulse-pounding account of the first time in history that the FBI’s Behavioral Science Unit created a psychological profile to catch a serial killer. Ron Franscell joins me on Murder Most Foul.