Cold Case: Season 2, Episode 6

2 - 6: The Sleepover

Lilly reopens a 1990 murder case in which a prep-school girl with bizarre markings on her body was found dead in a local swimming hole, after a present-day victim with similar markings is discovered at the same place. The investigation reveals that the victim of the earlier crime was routinely tormented by a trio of classmates who invited her to a sleepover the night she was killed.