Superman was probably the most supportive of the war effort, even encouraging readers to buy war bonds, recycle rubber and scrap iron, and donate blood. Nevertheless, he was investigated by Army Intelligence. Had the Man of Steel turned traitor? Not exactly. After Superman writer Alvin Schwartz used the term “cyclotron” in a story, the War Department became concerned the writer was receiving leaks from the Manhattan Project. In truth, he had simply recalled the term from an old issue of Popular Mechanics.