I think Sheriff Brown has a flare for being dramatic. The whole thing is already bizarre, though. I can’t think of a manhunt of this magnitude for a murder. Posting billboards, electronic billboards, etc. His picture is one of the most posted manhunt photos I can remember.
Given that the FBI already has a dossier on him there is the possibility that he can be tied to other open cases. If so, then the FBI certainly has reason to step up the manhunt.
Perhaps authorities realize they don’t have a clear picture of his background.