Is it possible that people can commit complex crimes – even murder – while they are sleepwalking? With only a dead victim and a zoned-out sleepwalker at the scene of the crime, it is hard to know for sure. Will extensive sleep tests performed on accused murderers reveal that it is possible to unknowingly kill someone in your sleep? If science says yes, what does the law say? And if we can commit murder in our sleep, what else might we do?