A teenager, Benjamin Elliott, is accused of fatally stabbing his twin sister, Meghan, while she slept. Benjamin claims he was sleepwalking and has no memory of the event, a defense supported by sleep disorder experts and a history of sleepwalking in his family. Prosecutors, however, remain unconvinced, citing inconsistencies in evidence and Benjamin's account. The case, "The Boy Who Killed His Twin," is being investigated by "48 Hours," exploring the possibility of sleepwalking as a defense in a murder trial.

Prepared by Emily Rhodes and reviewed by editorial team.