Final answer:
The Black Legion was a violent, secret society affiliated with the Ku Klux Klan, active in the 1930s and known for targeting minorities. It gained notoriety through the murder of Charles Poole in 1936.
Step-by-step explanation:
The Black Legion was a secret society and a paramilitary offshoot of the Ku Klux Klan that operated in the United States during the 1930s. Its members were known for their violent acts against African Americans, Catholics, Jews, immigrants, and others they considered non-American or against their ideology. The Black Legion was first introduced to the public through a series of arrests and trials when their crimes came to light, mainly through the murder of Charles Poole, a Works Progress Administration worker, in 1936. This vigilante group had a significant impact on society and politics of the era, especially in areas of the Midwest like Michigan and Ohio.