
A. Mitchell Palmer, former attorney general of the United States, leaves Senate Office building in Washington on March 1, 1924. Immigrant roundups in late 1919 and early 1920 are known in history books as the Palmer raids, after Palmer who ordered them. He was aided in his efforts by a young Justice Department attorney named J. Edgar Hoover, whose experience helped lead to the emergence of the Federal Bureau of Investigation. (AP Photo)