A 12-year-old girl stabbed in the name of a mythical online creature; a 24-year-old man posts his darkest fantasies before slaying three coworkers.

In 1977, aspiring actress Christa Helm gets murdered in West Hollywood; she becomes known for her secret diary, detailing romantic encounters with celebrities; her death remains one of Hollywood's greatest mysteries.

A Hollywood studio executive and devoted family man vanishes into thin air one night; as investigators dig into the case, they uncover dark secrets, and the details of man living a double life.

Richard Ramirez was a satanic killer terrorizing an entire state who sexually assaulted his victims. Aileen Wuornos, a highway hooker with a gun. Doug Clark and Carol Bundy prowled the Sunset Strip for sex and victims.

When obsession meets celebrity, the results can be fatal; rising music star Christina Grimmie is gunned down by a crazed fan; singer Bjork survives a bizarre plot by a man who takes his own life.