Franz von Rintelen (died 1949) was a German spy working in the United States during World War I.
He came from a banking family with good connections in American banking. He spoke fluent English.
He was sent to the United States in 1915, while the U.S. was still technically neutral. His mission was to sabotage American ships carrying munitions and supplies to the Allies. Arriving in New York City, he posed as a businessman and, with Heinrich Albert, set up a dummy corporation called Bridgeport Projectile, through which he purchased gunpowder, which he then destroyed.
He worked with a technician to develop time-delayed incendiary devices known as pencil bombs, which were then placed in the holds of American merchant ships to cause fires in the ships' holds so that the crew would throw the munitions overboard.
He also organized the Labor's National Peace Council to foster strikes to slow American aid to the Allies.
His work was largely successful and probably included some part in the Black Tom explosion in 1916. His colleagues were not all pleased with his success, and Franz von Papen (later Chancellor of Germany) sent a telegram to Berlin complaining about him. The telegram was intercepted and deciphered by British Naval Intelligence. As he sailed back to Germany on a neutral Dutch ship, he was captured at Southampton, England and interned in Atlanta, Georgia for three years.
He returned to Germany in 1920, a forgotten man. He moved to England, where he died.
Von Rintelen wrote The Dark Invader: War-Time Reminiscences Of A German Naval Intelligence Officer which was published in 1933.