SNEAK PEEK: A bitter mystery turns into an ongoing nightmare during an all-new episode of Cold Case Files TONIGHT at 9/8c on A&E. | Cold Case Files

A cold case featuring a mother who vanished without a trace heats up a decade later when her sister launches a social media campaign to solve her mysterious disappearance. An all-new episode of Cold Case Files starts TONIGHT at 9/8c on A&E. | Cold Case Files

The hunt for this teen's murderer ends up uncovering a serial killer in this clip from Season 2. | Cold Case Files

What starts with a disturbing discovery leads investigators on a long path toward justice. #ColdCaseFiles | Cold Case Files