Here's one that took the U.S. public by surprise. Robert Hanssen, a 25-year FBI agent and church-going family man, was also a long-time double agent for the Soviet Union.
Hanssen worked as a liaison between the FBI and the office responsible for tracking the identities of spies working in the U.S. By the early 2000s, investigators believed he had spent 20 years sharing state secrets. They suspected he'd revealed the identities of dozens of Soviet agents working for the U.S. and led to the killing of several.
And Hanssen didn't stop there. He fed the Soviet government U.S. plans, including the procedures for dealing with and retaliating against a Soviet nuclear attack. Although he was paid $1.4 million and some diamonds for his efforts, colleagues said he seemed to have been more motivated by playing the spy game than by greed.
Hanssen was caught when the FBI paid a former KGB agent to disclose the identity of the mole operating in the FBI. In 2002, Hanssen pled guilty to 15 counts of espionage and conspiracy. He was sentenced to life in prison [sources: CNN, New York Times].
Author's Note: 10 of History's Most Notorious Traitors
I've always thought of espionage as something confined to the books my husband reads or a late-night James Bond movie marathon. Turns out, I couldn't have been more wrong. Spies played pivotal roles in some of history's greatest mysteries and still exist today. Makes you look at your neighbor a little differently, doesn't it?
- Biography. "Benedict Arnold." (May 25, 2013) http://www.biography.com/people/benedict-arnold-9189320
- Biography. "Ezra Pound." (May 25, 2013) http://www.biography.com/people/ezra-pound-9445428?page=1
- Biography. "Judas Iscariot." (May 25, 2013) http://www.biography.com/people/judas-iscariot-9358799
- CNN. "Ex-FBI Spy Hanssen Sentenced to Life, Apologizes." May 14, 2002. (May 25, 2013) http://archives.cnn.com/2002/LAW/05/10/hanssen.sentenced/
- Creighton, Linda. "Benedict Arnold: A Traitor, but Once a Patriot." U.S. News and World Report. June 27, 2008. (May 25, 2013) http://www.usnews.com/news/national/articles/2008/06/27/benedict-arnold-a-traitor-but-once-a-patriot
- Encyclopaedia Britannica. "Vidkun Quisling." (May 25, 2013) http://www.britannica.com/EBchecked/topic/487555/Vidkun-Quisling
- Jesus Central. "Matthew's Biography of Jesus: Chapter 27." (May 25, 2013) http://www.jesuscentral.com/ji/life-of-jesus-ancient/biography-of-jesus-christ/who-is-Jesus-by-matthew/gospel-of-matthew-27.php?lgZ=en&ccZ=&vrZ=&vrZ=&scZ=&add=Read&show=Journals
- History. "Jesse James Shot in the Back." (May 25, 2013) http://www.history.com/this-day-in-history/jesse-james-shot-in-the-back
- Lofty, Carrie. "Cowards: Robert Ford." Unusual Historicals. April 27, 2011. (May 28, 2013) http://unusualhistoricals.blogspot.com/2011/04/cowards-robert-ford.html"
- Melok, Bobby. "Fathead, Company Owned by Dan Gilbert, Cuts LeBron James pics to $17.41, Benedict Arnold's Birthyear." New York Daily News. July 9, 2010. (May 25, 2013) http://www.nydailynews.com/sports/basketball/fathead-company-owned-dan-gilbert-cuts-lebron-james-pics-17-41-benedict-arnold-birthyear-article-1.465840
- New York Times. "F.B.I. Paid $7 Million for File On American Spying for Russia." Oct, 18, 2002 (May 28, 2013). http://www.nytimes.com/2002/10/18/us/fbi-paid-7-million-for-file-on-american-spying-for-russia.html
- Noe, Denise. "Mata Hari." TruTv. (May 25, 2013) http://www.trutv.com/library/crime/terrorists_spies/spies/hari/1.html
- Pierce, J. Kingston. "Tokyo Rose: They Called Her a Traitor." American History. October 2002. (May 25, 2013) http://www.historynet.com/tokyo-rose-they-called-her-a-traitor.htm
- Spy Museum. "The Cambridge Five." (May 25, 2013) http://www.spymuseum.org/education-programs/spy-resources/background-briefings/the-cambridge-five/
- Vernon, Jennifer. "Ides of March Marked Murder of Julius Caesar." National Geographic. March 12, 2004. (May 28, 2013) http://news.nationalgeographic.com/news/2004/03/0311_040311_idesmarch.html
Charles 'Pretty Boy' Floyd lived a life of crime. HowStuffWorks looks at why the FBI named him Public Enemy No. 1, and how a famed agent killed him.