Barbie Hellman is a wealthy American divorcee. She lives next door to Alicia and Gabriel Berenson at the time of the murder, and she is the one who hears gunshots and calls the police. Though Alicia cannot stand Barbie’s endless, self-absorbed chatter, she does confide in Barbie that she fears a mysterious man is following her. Later, Barbie uses this information to claim that she and Alicia were close confidantes. Theo sees Barbie as the ultimate narcissist, a stark contrast to his own, more empathetic method of relating to others.