Benedict Arnold

The quintessential turncoat, Benedict Arnold actually was quite the patriot at the beginning of the Revolutionary War. He had been involved in many victories over the British, but frequently was overlooked for advancement and honors. After another general claimed responsibility for his success at the Battle of Saratoga in 1777, Arnold grew disillusioned. His wife had died during his endless campaigns, he was broke, and Congress kept cutting funding for the military. Around this time, he was reprimanded, unfairly, on two counts of dereliction of duty. Soon after he wrote to British Major John Andre and made a deal to sell his command of West Point to the British for 20,000 pounds ($3 million in today’s dollars). Andre was intercepted with the plan and hanged. Arnold escaped and accepted a commission with the British Army, leading attacks on Virginia and Connecticut, before moving to London. He died in 1801.

Timothy Webster

Timothy Webster, a British-born former New York City police officer, was hired by Allan Pinkerton, who called himself the “Chief of the United States Secret Service,” and sent to Richmond to do reconnaissance work in the Confederate capital. His cover was that he was a secessionist courier from Baltimore. According to Pinkerton, everyone who met Webster, “yielded to the magic of his blandishments and was disposed to serve him whenever possible.” He quickly ingratiated himself with Confederate officials, including Secretary of War Judah P. Benjamin, who asked him to start carrying messages to secessionists in Baltimore. This allowed him to deliver actual Confederate documents to Pinkerton, along with his observations. In 1862, captured Pinkerton operatives blew Webster’s cover. He was arrested, tried, and hanged, despite a letter from Abraham Lincoln to Confederate President Jefferson Davis asking that Webster’s life be spared.

Mata Hari

Born Margaretha Geertruida Zelle in Holland in 1876, Mata Hari moved to Paris in 1905 and became famous for her Asian-inspired exotic dancing. She had learned something of Indian and Javanese dancing styles when she had lived in Malaysia with her husband, who was in the Dutch Colonial Army. Her fame grew and she acquired lovers throughout Europe, many of them very powerful. After the outbreak of World War I in 1914, the German consul in Holland tried to recruit her as a spy. She took his offer of 20,000 francs, though it seems she never actually did any spying for him. The French soon asked her to spy for them as well, but they quickly learned that she was technically in the employ of the Germans. She was arrested in 1917, tried, found guilty, and executed on October 15. However, the case against her was flimsy and much of the evidence against her was circumstantial. Thirty years later, one of the prosecutors declared, “There wasn’t enough evidence to flog a cat.”

Dusko Popov

The man who inspired James Bond, Yugoslavian Dusko Popov was recruited by MI5 to work as a double agent during World War II— between 1940 and 1944. He pretended to give the Germans important military intelligence, when he was really relaying information about Germany back to the British. He communicated invisible ink on postcards, and a special code of microdots. Unfortunately, his code name was not quite as cool as 007’s. At first he was called Agent Scoot. But his “appreciation for the ladies” and his love of threesomes earned him the name Agent Tricycle.

Arthur Owens

Arthur Owens spent years in exile, reviled as a Nazi spy, but he actually was a double agent working with MI5. The Germans recruited Owens, a broke inventor and Welsh nationalist, while he was on a business trip to Belgium in 1935. He did give the Germans important information about the British military buildup before the war. But he was quickly recruited by MI5 to work as the Britain’s first double agent. In 1941, he was placed in Dartmoor prison, where he took information from German inmates and fed it back to his bosses. Documents released in the 1970s revealed his dual role, but unfortunately, they did not have a widespread impact and did nothing to improve his reputation as a traitor.

Harold ‘Kim’ Philby

Harold “Kim” Philby was one of 40 Cambridge students recruited to work as spies by the Soviet Union, but he rose far higher, was more trusted, and lasted longer than the rest. He started as a KGB informer in the 1930s in London, while working as a London Times correspondent. In the 1940s, he joined the Secret Intelligence Service, became one of its most trusted agents, and worked as a mole for the Soviet Union for nearly eight years. He even received the Order of the British Empire in 1945. In 1949, he started working as a British Intelligence liaison between the FBI and the CIA. Philby finally came under suspicion in 1951, but was not caught outright until January 1962, because his bosses refused to believe evidence against him. Three days after being accused of espionage, he fled to the Soviet Union where he died in 1988.

Aldrich Ames

Aldrich Ames had been working for the CIA for 31 years when he and his wife were arrested on espionage charges in 1994. It turned out he had been selling information to the Soviet Union since 1985, with an emphasis on selling. In need of cash, he had volunteered his services to KGB agents at the Soviet embassy in D.C. By 1989, the Soviet Union had already paid him $1.88 million, and he continued to sell information after that. Meanwhile, the CIA and the FBI were concerned that many of their sources inside the U.S.S.R. were being identified and executed. This mystery, coupled with Ames’ inexplicable sudden wealth, led the organization to launch an investigation. When he was arrested in 1994, Ames admitted to compromising the identities of the sources.

Robert Hanssen

FBI counterintelligence agent Robert Hanssen, a father of six, spied for the Soviet Union and then the Russian Federation for more than 15 years until he was caught in 2001. Over the years, Hanssen received payment of $600,000 cash, $50,000 in diamonds, and he had been promised $800,000 in a Russian bank account for his espionage activities. However, unlike many American turncoats, he was not spying purely for the money. In fact, he had idolized British spy Kim Philby growing up. He once wrote to his Russian contact, “Want me to lecture in your 101 course in my old age? I would be a novelty attraction. I’d decided on this course when I was 14…I read Philby’s book.”

Human Khalil Abu-Mulal al-Balawi

Human Khalil Abu-Mulal al-Balawi, a 36-year-old doctor from Jordan, detonated a suicide bomb at a CIA base in Khost, Afghanistan, on December 30, 2009. The attack killed eight people. He had been recruited by the Jordanian intelligence service and then taken to Afghanistan to infiltrate al Qaeda. Eventually, he offered to reveal information about top al Qaeda operatives and was taken to the CIA base for a meeting. Because he was thought to be a trusted informant, he was not searched thoroughly when he arrived at the base and was able to carry off the fatal bombing. One former official said of the incident, “Double agent operations are really complex. The fact that they can pull this off shows that they are not really on the run. They have the ability to kick back and think about these things.”

Second Al Qaeda Underwear Bomber

When authorities foiled a May 2012 plot by al Qaeda in the Arabian Peninsula to blow up a U.S.-bound plane using an underwear bomb, they cryptically said the bomber was no longer a threat. It would later emerge that he was no longer a threat because he was an undercover intelligence agent all along, and had been inside al Qaeda providing the U.S. and Saudi Arabia intelligence information for a long time. He not only had foiled the plot, but also had delivered the underwear bomb to the CIA. The operative has since left Yemen and reportedly is safe.