Nov. 5, 1989 was the day Betty Broderick snapped.

E! News has an exclusive preview from Oxygen's Snapped: Betty Broderick, which details the chilling real-life 911 call that came in after Betty shot and killed her ex-husband Dan Broderick in San Diego following a tumultuous divorce.

"A frantic call comes in from Brad Wright. He says, 'Oh my god, something terrible has happened," author Loretta Schwartz-Nobel recalls in the clip.

"We were responding to the call on a house on Cyprus Way," former San Diego police officer Dominic Valaile, who was first to arrive at the scene of the crime, recounts.

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