But it was the manifesto that really put kaczynski's brother over the threshold and motivated him to contact the fbi and say that he thought he knew about -- he knew who the author was. >> what more if anything can you tell us about the evolution of this criminal profiling that was kind of born at this time? >> so that's become a mainstay of the fbi. as you know, it's frequently captured in lore about the bureau in movies and tv series, things like that. but it's become one of the most relied upon assets in these particularly hard cases, cold cases, you know, bombing campaign like this one, mu...