I have a special agent (FBI) who is working on a case about some magical serial murders. Even when he at first is a skeptic about magic, he is intrigued about the case because it seems more like two parties, one on the run from the other, and he wants to know who is running from what. Those being chased are two runaway teens, one turned into a zombie-like monster. The spell that turned him into that gave them both magical powers (her immunity and ability to control him when she needs and him the ability to shape change in order to devour people like an octopus). Those chasing them are a young boy who is technically in a coma and a monster who inhabits his body. The monster can change the shape and state of of objects, and can use a 'shadow' that grows teeth and bites. How would he FBI agent figure out one is running from the other? How much evidence would he need to identify these people to make that deduction? What actions would these people take to still avoid the police, but the police notice the different patterns?