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

Last week, Natalie Morales sat down in prison with the infamous Drew Peterson for his first network interview in more than a decade. Watch it tonight at 9/8c on an all-new 2-hour Dateline. | Dateline NBC

Friday on an all-new Dateline at 10/9c... | Dateline NBC

None of it made sense… What happened on that cold, brutal morning? Find out tonight at 9/8c on a classic Dateline on NBC. | Dateline NBC