For British spies during World War II, one of the greatest challenges came from a colleague: one Agent Fifi, a beautiful woman tasked with getting trainee agents to leak their secrets. Fifi was long thought to be an urban legend, but newly opened documents from Britain's National Archives show that she was real, the Washington Post reports. Fifi was her code name; her real name was Marie Christine Chilver, and she was "one of the expert liars of the world," according to a British airman she helped return to England after he was shot down.
That adventure earned her the attention of Britain's Special Operations Executive, the BBC reports. Her new job was to pose as a French freelance journalist, meeting trainee agents in bars and testing their discretion. The majority of trainees failed the test, the BBC notes, and that could lead to their firing. The half-English, half-Latvian Chilver, who spoke many languages, was "a symbol of seduction—not surprising, since she’s said to have bedded trainee agents to find out whether they talked in their sleep," writes a National Archives researcher. After the war, she conducted intelligence work in Germany and set up an animal charity in Latvia, the Independent reports; she died in 2007. "She didn’t have many friends," says one worker at Chilver's charity. "I think she led a lonely life."