Amy Elizabeth Thorpe Amy Elizabeth " Betty " Thorpe ( 22 November 1910 – 1 December 1963 ) was , according to William Stephenson of British Security Coordination , an American spy , codenamed " Cynthia , " who worked for his agency during World War II . British Security Coordination was a cover organization that had been set up in New York City by the British Secret Intelligence Service ( MI6 ) in May 1940 . Early life . Amy Elizabeth Thorpe was born on 22 November 1910 in Minneapolis , Minnesota , United States . Her father was a U . S . Marine Corps officer . Her mother , Cora Wells , was the daughter of a Minnesota state senator . Thorpe was introduced at a young age by her parents to the Washington social scene and quickly became immersed in the world of diplomatic intrigue . By the time she was in her late teens , she had been romantically linked to foreign diplomats many years her senior . In 1936 , Arthur Pack , second secretary at the British embassy in Washington , became Thorpe ' s choice for a husband ; but in the 1930s , in the wake of two quick pregnancies and Pack ' s work - connected travels , the relationship became distant . According to William Stevenson ' s best - selling " A Man Called Intrepid " , Thorpe traveled frequently to Europe , nominally to support Pack ' s work . In reality , according to Stevenson , she had embarked upon secret intrigues , working for both sides in the Spanish Civil War . World War II . According to William Stephenson Amy Elizabeth Thorpe came to his attention in winter 1937 , after joining her husband on assignment in Warsaw . Stephenson , Churchill ' s wartime head of British Security Coordination from May 1940 , says that Thorpe was especially useful to Britain ' s Secret Intelligence Service ( MI6 ) in 1938 for her work in helping the Allies understand how the Enigma machine was used and that Polish mathematicians were breaking Enigma ciphers . Enigma machines would be used throughout the coming war by the Axis Powers , whose enciphered messages would routinely be read at Britain ' s Bletchley Park . Stephenson ' s story is disputed by historian Richard Woytak , who describes it as one of several examples of disinformation , by best - seller authors and others , concerning how the results of Polish cryptologic work on Enigma reached the western Allies . The Polish successes , which began in late 1932 , gave inception in July 1939 to the Ultra operation that would be conducted during World War II at Bletchley Park , fifty miles northwest of London . Another critic , T . J . Naftali , writes : " The Intrepid myth included the claim that Sir William [ Stephenson ] had contributed to the actual process of decryption by providing British codebreaker s with a copy of the German Enigma machine and by encouraging them to use computers to ' unbutton ' German signals . " By the time World War II broke out in Europe in 1939 , Thorpe was out of Poland and had returned to Washington , D . C . , where , according to the late American TV journalist David Brinkley , she resumed her tour through the American capital ' s diplomatic social scene , often as mistress to married foreign diplomats . According to Stevenson , Thorpe used the access gained by her romantic relationships to obtain strategic secrets about Nazi Germany , Vichy France and Fascist Italy , and to extract practical knowledge needed to place spies in Fortress Europe . In 1942 , according to Stevenson , she obtained codes from the Vichy French embassy in Washington which assisted the Allied invasion of North Africa . According to Stevenson , a love affair that Thorpe conducted with the Italian naval attaché Admiral Alberto Lais was especially productive and gained western Allied leaders early strategic insight into Axis war plans in the Mediterranean . In 1967 , however , the Admiral ' s heirs sued British author , H . Montgomery Hyde , in an Italian court for defamation , insisting that Lais ( who had died in 1951 ) had not betrayed military secrets , and won . In 1988 , Lais ' two sons protested publication of the seduction account in David Brinkley ' s best - selling " Washington Goes to War " and persuaded the Italian defense ministry to publish denial ads in three leading East Coast newspapers . The Italian Naval Enigma message leading to Italian defeat at the Battle of Cape Matapan was broken at GS & CS , Bletchley Park using Dilly ' s rodding method without a codebook . This debunks Hyde ' s theory that a codebook obtained from Admiral Alberto Lais was responsible . Postscript . Thorpe is reported to have later said about her sexually active war years : After her nearly estranged husband Arthur Pack killed himself in 1945 , Thorpe married one of her best informants , Charles Brousse , former press attaché at the Vichy French embassy in Washington . The couple lived together quietly in France until she died of throat cancer on 1 December 1963 .