Investigators walked into a mystery that would turn their world upside down… Watch tonight at 9/8c on a 2-hour Dateline Weekend Mystery on NBC. | Dateline NBC

Tonight on a new Dateline, the latest chapter in this hair-raising tale, featuring new evidence, explosive testimony and the prosecution's new star witness. Watch at 9/8c on NBC. | Dateline NBC

A medical mystery was about to turn into a full-on police investigation… Tonight on an all-new Dateline at 10/9c on NBC. | Dateline NBC

Finally, the last mystery in the case began to unravel… Dateline new tonight at 9/8c on NBC | Dateline NBC