When Charles Lindbergh became the first person to fly solo across the Atlantic in 1927, it made him an international hero. Five years later his infant son was kidnapped and killed, transforming him into a tragic figure. Now, the world may be seeing another side of the man: passionate adulterer with a secret life. According to the German daily Süddeutsche Zeitung, the aviator, who had six children with his wife, Anne, carried on a 17-year affair with a Munich hatmaker named Brigitte Hesshaimer lasting until his death at 72 in 1974—and producing a daughter and two sons.

It was the purported daughter, Astrid Bouteuil, 41, who broke the story. Sworn to silence until her mother died two years ago, Bouteuil said Brigitte met Lindbergh through a friend. Astrid and brothers Dyrk, 44, and David, 36, knew him as Careu Kent, a family friend who visited often, could wiggle his ears and cooked a mean omelette. There were clues—once her mother saw Bouteuil reading a LIFE article on Lindbergh and ripped it out of her hands. In the early '80s Bouteuil discovered photos and love letters in the attic, some signed "Charles." The most telling, sent when her family was moving, read, "I am most anxious how our children will like their new house." She then asked if Lindbergh was her father, and Brigitte tearfully owned up. When Bouteuil refused to give the letters back, her mother wailed, "You don't know what you are doing!"

Reserving comment, Lindbergh's U.S. family has asked for privacy. Bouteuil, meanwhile, said she came forward so the affair wouldn't be "buried in the depths of oblivion."