Criminal Profiler Examines Possible Clues in Indiana Teens’ Murders

America's foremost criminal profiler is now giving his insight into the mystery of who killed two Delphi, Indiana, teens. Abby Williams and Libby German were found dead after they went for a hike in February 2017. More than two years later, authorities have yet to catch their killer. Among the few clues is video from Libby's cellphone showing a man walking toward the two girls and a recording in which a man apparently says "guys down the hill."