Talk to the NHS Retirement Fellowship Cambridge Branch Codebreaker - Elizabeth Friedman, who broke up a Nazi Spy Ring

During World War II, Friedman's Coast Guard unit was transferred to the Navy, where they were the principal U.S. source of intelligence on Operation Bolívar, the clandestine German network in South America. Prior to the Japanese attack on Pearl Harbor that brought the U.S. into the war, there was concern that Germany could eventually attack the U.S. via Latin America. The Nazi authorities also saw Latin America as a potential opportunity to outflank the U.S. While the FBI was given responsibility for countering this threat, at the time, the one U.S. agency with staff experienced in detecting and monitoring clandestine spy transmissions was the Coast Guard, due to its earlier work against smugglers, and Friedman's team was its sole cryptanalytic asset.