Its more about them trying to learn how to read a person and the signs from their past that may have lead them to be serial murderers. Using that information, the FBI agents capture other criminals before they get to far into their serial murdering life. I don't think a single person has shot a gun at another human in this show so far.
David Fincher is a good director and has done a lot of famous work like Fight Club and Seven. He seems to enjoy working with deviant material. David was attached to film an animated adaptation of my favorite comic book series The Goon but I think that has fallen through. The Kickstarter was over 5 years ago.