America's foremost criminal profiler is now giving his insight into the mystery of who killed two Delphi, Indiana, teens back in 2017. Abby Williams and Libby German were found dead after they went for a hike in February 2017 at a popular trail in their area.
More than two years later, authorities have yet to catch their killer despite thousands of tips and even evidence collected by the girls before their murder. 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."