'20/20' INVESTIGATES THE DISAPPEARANCES OF LAUREN SPIERER AND KELSIE SCHELLING

'20/20' Airs Saturday, January 7, on ABC

It's been more than five years since the disappearance of Indiana college student Lauren Spierer. A "20/20" investigation by ABC News Chief Investigative Correspondent Brian Ross and former FBI agent and ABC News Consultant Brad Garrett finds new hope in a cold case.

After a late night of partying, the 20-year-old coed from Westchester, New York, was last seen on June 3, 2011, at 4:30 a.m. on a Bloomington street corner. Her disappearance, which made national headlines, was never solved, and Lauren's heartbroken parents, Rob and Charlene, have led a five-year search to find out what happened to their daughter. "It's the not knowing what happened to her, where she might be, you know, that's unbearable," Lauren's mother told Ross.

Ross and Garrett, with the help of private investigators hired by the family, work to untangle the case and piece together several intriguing and chilling leads. Was Lauren abducted by a predator on the prowl? Was she killed by members of a violent motorcycle gang? Or does someone she partied with that night hold the key to the mystery? Follow along with the investigators as they track down and interview fellow students, a former member of a notorious local biker gang, and a witness with his startling account of Lauren's final hours. (OAD: 6/24/16)

Twenty-one-year old Kelsie Schelling mysteriously vanished into thin air in Pueblo, over three years ago. The family says surveillance video, text messages and other evidence point to her boyfriend's involvement, yet to their outrage, police have not yet classified the case as a homicide and have not charged him with a crime. But then a series of Facebook messages to Kelsie's mother raise new theories. Is the missing girl's disappearance prompting someone to attempt extortion? "20/20" Correspondent Ryan Smith investigates and confronts those behind the mysterious plot and uncovers developments about what really happened to Kelsie. (OAD: 5/13/16)

"20/20" airs on SATURDAY, JANUARY 7 (9:00- 11:00 p.m. EST) on ABC.

"20/20" is anchored by Elizabeth Vargas and David Muir. David Sloan is senior executive producer.