Hoover must have been astonished to learn that an American army general was refusing to cooperate with an FBI investigation. On June 13, 1946, Hoover personally wrote Groves, asking him to reveal what Oppenheimer had told him about George Eltenton. Groves replied on June 21, politely declining to furnish this information, “as it would endanger” his relationship with Oppenheimer. Not many men in Washington defied a direct request from the director of the FBI, but in 1946 Groves had a lot of prestige and self-confidence.
