College student Mollie Tibbetts disappeared from the small Iowa town of Brooklyn. The 20-year-old woman former high school track star went out for an evening jog and never came home. After a month-long search, Tibbets' body is found in a cornfield, covered by stalks. The man who put Tibbetts there, led police to the body. The medical examiner concluded she died from "multiple sharp force injuries." Forensics expert Joe Scott Morgan explains the injuries.