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?

When veteran broadcaster Alistair Cooke died in 2004 few suspected that he was yet to uncover his greatest story. What happened to his body as it lay in a funeral home would reveal a story of modern day grave robbery and helped smash a body-snatching ring that had made millions of dollars by chopping up and selling-off over 1000 bodies. Dead bodies have become big business.

Each year millions of people's lives are improved by the use of tissue from the dead. Bodies are used to supply spare parts, and for surgeons to practice on. Horizon investigates the medical revolution that has created an almost insatiable demand for body parts and uncovers the growing industry and grisly black market that supplies human bodies for a price.

Off the Chain is an unprecedented look into the underground world of dog fighting. Beginning with a history of the American Pit Bull Terrier, the film explores the evolution of the breed. Classic film and television footage show the popularity of what was once considered a noble and trustworthy family pet. Examine how this breed went from America's dog to public enemy number one.