At this time Hemingway was worried about money and about his safety. He worried about his taxes, and that he would never return to Cuba to retrieve the manuscripts he had left there in a bank vault. He became paranoid and thought the FBI was actively monitoring his movements in Ketchum. The FBI had opened a file on him during World War II, when he used the Pillar to patrol the waters off Cuba, and had the agent in Havana watch Hemingway during the 1950s. The FBI knew Hemingway was at the Mayo Clinic, as an agent documented in a letter written in January 1961.