When 17-year-old Brittanee Drexel stopped answering text messages mid-conversation during a spring break trip in April 2009, her friends and family instantly knew something was seriously wrong. Drexel — who was last seen on video camera footage leaving a hotel in Myrtle Beach, South Carolina — had seemingly vanished into thin air, creating a heartbreaking mystery that would haunt her friends and family for more than a decade. Now, "20/20" gives viewers an exclusive inside look at how a new FBI team assigned to the case finally brought justice to Brittanee with the arrest of convicted sex offender Raymond Moody and brings viewers inside the dramatic courtroom confrontation between Brittanee's mom and her daughter's killer for the first time.