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The wrong haircut -

East Germany had a peculiar spy unit during the Cold War, which consisted of suave men who engaged in "sexpionage." Their mission was to go to West Germany, where they seduced women and sweet-talked them into spilling secrets.

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The wrong haircut -

However, many of these "Romeo spies" sported the traditional haircut worn by men in East Germany, and this small detail was enough to give them away as spies.

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Billing NASA -

Not only was Stewart Nozette (third from the left) a scientist working for the Department of Energy, the Department of Defense, and NASA,  he even served on President George H. W. Bush's National Space Council.

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Billing NASA -

Nozette set up a nonprofit called Alliance for Competitive Technology that ended up under investigation after invoicing NASA way more than expected. Nozette's nonprofit was billing NASA US$140,000 but had less than $20,000 in salaries. The numbers just didn't add up.

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Billing NASA -

The investigation found that money was being used for suspicious expenses like three mortgages and nine different credit cards, among other things. It turns out that Stewart Nozette had tried to sell information to the Israeli government, but the person he was dealing with was actually an FBI agent in disguise.

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Extravagant purchases -

Aldrich Ames worked with the CIA as a counterintelligence analyst for 31 years, ending up in Washington, D.C. When he found himself in financial ruin after a messy divorce, he began spying for the Soviets to make some extra cash.

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Extravagant purchases -

After earning around US$2 million from the Soviets, Ames went on a spending spree. He bought himself an expensive new house and a Jaguar car, paying for it all in cash.

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Extravagant purchases -

This triggered alarm bells and the FBI started surveilling him. Aldrich Ames pleaded guilty to espionage charges and was sentenced to life imprisonment.

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A bouquet of flowers -

Sometimes it takes a body language expert to spot something unique that most people would miss. This was the case for former FBI Agent Joe Navarro, who caught a spy solely based on how he carried a bouquet of flowers.

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A bouquet of flowers -

Unlike most people in the US, who carry a bouquet by the base with the flowers up, the suspect gripped the bouquet towards the top, with the flowers upside down and the bouquet held behind him. This is how some people carry flowers in Eastern Europe, and that was all the FBI needed to make a move. It turns out, the man was indeed a spy.

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Littering -

Christopher Boyce (pictured) was the son of  a CIA agent who got caught up on the wrong side of the Cold War. Boyce recruited his childhood friend Andrew Daulton Lee and hatched a plan to sell information to the Soviets. Lee would drive to a Soviet embassy in Mexico, where he'd trade the state secrets given to him by Boyce.

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Littering -

Lee delivered the information by dropping papers over the Soviet embassy gate. This would be his downfall, as he was spotted by the Mexican police and arrested for littering. Following an investigation that exposed their plan to sell US secrets to the Soviet Union, both men were eventually arrested.

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A carrier pigeon -

Sarah Aaronsohn was a Jewish woman living in Turkish-occupied Palestine who ended up working as a spy for the Allies during World War I. As a member of the Jewish spy ring Nili, Aaronsohn's mission was to pass information about the Ottoman Turks to the Allies.

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A carrier pigeon -

One day, a carrier pigeon carrying intel was intercepted by the Turks, which led to her being captured. She was tortured, but managed to take her own life before her captors could get information out of her. In the end, Aaronsohn's work helped the British drive the Turks out of Palestine.

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A thick accent... and a sausage! -

Josef Jakobs bought his way out of a concentration camp by striking a deal with the Nazis: he'd become a spy for them in Britain. On mission day, Jakobs parachuted from a plane onto British soil.

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A thick accent... and a sausage! -

Unfortunately, he broke his ankle when he landed, leaving him helpless. He decided to fire a pistol to get some attention. He was unlucky again, as it was English soldiers who found him. What they found was a man with a thick German accent carrying £500, a passport, and, reportedly, a German sausage. Jakobs was instantly pegged as a German spy. He was executed at the Tower of London after being found guilty of espionage.

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A concerned mother -

Polish Baron George Sosnowski enlisted both his wife and a woman he once had an affair with to work with him as spies against the Nazis. Both Baroness Benita von Berg (pictured) and Renate von Natzmer worked at the German Ministry of Defense—a privileged location to get intel for the Allies.

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A concerned mother -

Noticing that her daughter was working late hours, Renate von Natzmer's mother decided to go to the ministry and complain about how much her poor daughter was working. This, of course, rang alarm bells in the ministry. Both women were found to have been passing information to the Allied forces via Sosnowski, and were arrested and executed as a result.

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Losing a watch -

Belgian nurse Marthe McKenna was working in a hospital in German-occupied territory in 1915 when she was recruited by the British and became a spy.

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Losing a watch -

McKenna was a successful spy, until she lost her wristwatch with her initials engraved on it at a German weapons depot. The Germans found it and put an anonymous ad up saying that a watch had been found. The nurse fell for it and responded to the ad. She was caught.

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Morse code -

David Owen Dodd was a young spy for the Confederacy during the American Civil War. He'd present a pass and a birth certificate to prove he was underage so that he could travel across enemy lines. He traveled to Little Rock, Arkansas, and brought back information.

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Morse code -

One day, he got lost in the woods and ended up behind enemy lines. When he tried to cross the border, he didn't have a pass, but showed the soldiers his birth certificate and a notebook he carried.

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Morse code -

The notebook contained a Morse code message with the locations of Union troops. The Union soldiers were able to decipher it and arrested him. Dodd was then sentenced to death.

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A delayed train -

American spy James J. Andrews planned to disrupt Confederate supply lines during the Civil War by hitting their railway infrastructure.

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A delayed train -

The plan was to capture the Confederate locomotive "The General" (pictured) at Big Shanty, Georgia, in what became known as the Great Locomotive Chase.

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A delayed train -

However, Andrews and the raiders had to pull aside to let a passenger train pass. This delayed their escape by one hour, which was enough time for the Confederate soldiers to catch them.

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Too much partying -

American William Colepaugh and German spy Erich Gimpel teamed up on a mission to gather intelligence for the Allied war effort. They were given everything they needed for the mission, including guns and US$60,000 (the equivalent of nearly $1 million today).

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Too much partying -

Colepaugh went on a party bender, spending US$1,500 in just a month. Gimpel was not impressed with his partner's dedication to the Nazi mission. Fearing repercussions from the Germans for his behavior, Colepaugh decided to turn himself in to the FBI.

Sources: (Grunge)

See also: The Everyday Life of a Modern Spy: Beyond the Movies

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