Teenager Claims Sleepwalking Defense in Twin Sister's Stabbing Death

A new episode of "Post Mortem" investigates a disturbing case involving a rare legal defense. Correspondents Anne-Marie Green and Erin Moriarty examine the death of a teenage girl, allegedly killed by her twin brother. Ben Elliott admits he stabbed his sister when they were both teenagers. However, his legal team argues he was not consciously responsible for his actions. They claim Elliott was sleepwalking during the incident. This defense, known as automatism, asserts a person can act without awareness or control. The "48 Hours" team will explore the details of the case and the complexities of this unusual legal argument.