Federal authorities hauled the daughter, Lucille Cameron, off to Rockford to hold her as a “material witness,” but couldn’t come up with enough to indict Johnson until another woman came forward and said Johnson had previously taken her across state lines. That enabled the Justice Department to indict Johnson under the Mann Act, named for Illinois Rep. James Mann, also known as the “white slave traffic” act. The law made it a crime to transport women for an “immoral purpose” and was driven by a racially motivated conspiracy theory that naive, innocent young women were being seduced or trapped into lives of prostitution and debauchery in America’s growing cities.