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July 13: 'Deadly Connection'

A beautiful young woman in Denver, Colorado goes out for the evening and never returns home. Weeks later, in a neighboring town, another young woman is found nearly murdered in her apartment. Was there a deadly connection between the two?

Watch the full episode below and learn more about Lydia Tillman on the 'Friends of Lydia' Facebook page:

Kenia Monge is an ambitious and responsible 19-year-old, but also independent. When she doesn't return home after a night out with friends, a terrifying mystery begins. Dateline NBC's Keith Morrison reports.