Again, not off the radar; Rossi was out there making a fortune writing popular non-fiction about serial killers (and probably consulting with Hollywood. "Mr. Rossi, we'd like to option your life story..." *g*)

I read "off the radar" as, "Whatthehell ever happened to So-and-So? He was gonna be the next big thing. Now he's not even a police radio dispatcher in East Podunk. You think he's maybe living in one of those refrigerator boxes under the interstate? Become a Buddhist monk? Joined a terrorist cell in Nicaragua? Because he got pretty weird there at the end..."