Reddit reviews Spy: The Inside Story of How the FBI's Robert Hanssen Betrayed America

If you liked the movie, check out this book about him. It goes into further details about his life. To be blunt about it, Robert Hanssen is the type of guy that could've became a serial killer if not for genetics, circumstances, environment or IDK what.

He reminds me a lot of BTK. Married man, father, working professional, smart, seemingly religious ---but with whole world/life/personality to him that he successfully keeps hidden away from his family & peers for decades. Obviously very different crimes but still very eerie.