How much of this is Google...
Love the show...Tivo it every week, but having worked on "reality" tv shows for years, I'm willing to bet that most of the B-Roll research we see is simply staged for the cameras.
I wouldn't be surprised if most of the HDs research is done by interns, and the Library scenarios, or the seemingly endless hours of research through books, are simply props put together by one of the producers for the audience's sake, or to sell the credentials of the "detectives."
Just my $.02