For years, Sandra Birchmore’s death was ruled a suicide, despite the disturbing questions surrounding her relationship with a Stoughton police officer who had known her since she was just 12 years old. Now, Matthew Farwell is on trial for allegedly grooming Sandra as a teenager, killing her while she was pregnant, and staging the scene to cover it up. But now, 50 witnesses take the stand, thousands of messages are examined, and one shocking DNA revelation turns the case upside down.