S6·E11 Werewolves

The CSI team investigates the murder of a man suffering from a congenital hypertrichosis, causing him to grow excessive body hair. Elements of the case suggest a connection with a belief in werewolves. The case leads to the victim's sister, who suffers from the same disease. Because of her condition, she'd been hiding from the world, but it turns out that she's hiding facts that are vital to solving the case.