ammunition -- that was found at the murder scene. >> but without the actual gun itself, the circumstantial case wasn't strong enough to charge smoot with murder. then, the crime lab released its ballistics report showing that marks on shell casings from the crime scene matched marks on a bullet found in smoot's home. his missing hand gun appeared to be the murder weapon. hat's a huge connection? >> it is pretty much the connection. >> in june of 2012, eight months after brooke was killed, shawn smoot was indicted on charges of first degree murder. did you immediately identify with her just being this young woman who was clearly so vulnerable? >> oh, absolutely. >> prosecutors bob edwards and tiffany starr smith saw this case as a relationship turned deadly. >> we're still talking about -- domestic violence. we're still talking about orders of protection, and all of the things that go wrong in those situations.