One of the many comic book series that tried to cash in on the 1930s craze, Mystery Men has become lost to obscurity. From the very limited information available on the Internet, however, we can deduce that these men of mystery did, indded, go after Hitler. In fact, they went after him in 1939, way before Captain America decided to pay Adolf a visit. This comic also claims that someone called "The Blue Beetle" is America's greatest hero, so I'm not sure how accurate it is.