[If Norton were to make a guess, he thinks this isn't the work of one, but multiple. The people behind a crime tend to leave behind traces when they're alone, and if they're in a group, their sloppiness can be covered up by the others.

Still, he can't act like that's the proper conclusion or else he might make a mistake.]

Digging up the first one to be affected is going to take some time-- that sort of thing needs you to work backwards. [And there are a number of people affected. If they could only speak... Well, they can't. Norton scratches the back of his head, making all the short hairs stand out.]

And even then, getting something out of the original patient is not going to be easy, chances are, you'll end up a patient yourself.