When Beverly Hills police respond to a 911 call at a mansion, they discover a widow, Violet Yacobi, dead below a staircase. How did she end up on the marble floor of her entryway, and was her death the result of a tragic accident or something more sinister? As detectives dig deeper, conflicting accounts and forensic evidence raise suspicion about Violet's dentist son Daniel Yacobi.

Kouri Richins, the Utah mother who made headlines for publishing a children's book about grief after her husband's death, was sentenced just last week to life in prison without parole for his murder. Prosecutors argued she poisoned her husband, Eric Richins, in a case that drew national attention. Now, jurors who heard the evidence are speaking out about what led them to convict her, including what they believe motivated the crime and why they reached their verdict. 48 HOURS correspondent Natalie Morales reports in the season finale, "Kouri Richins: Behind the Facade."