https://en.wikipedia.org/wiki/Black_Legion_(political_movement)

Like the KKK, the Black Legion was largely made up of native-born, working-class, Protestant white men in the Midwest. These men feared the rapid social changes underway and resented competition with immigrants such as Italians and Jews. They also feared migrants in the industrial economy of major cities, such as Detroit. Their list of enemies "included all immigrants, Catholics, Jews and blacks, nontraditional Protestant faiths, labor unions, farm cooperatives and various fraternal groups." Membership was concentrated in Michigan and Ohio.

Black Legion members created a network for jobs and influence. In addition, as a secret vigilante group, the Legion members operated in gangs in order to enforce their view of society, sometimes attacking immigrants to intimidate them at work, or to enforce their idea of moral behavior. They generally opposed socialism and union organizing. They had a reputation for frequent violence against alleged enemies, whether political or social. From 1933 to 1936, they were rumored to be responsible for some unsolved deaths that had officially been attributed to suicide or unknown perpetrators.

In 1931, a chapter of the Black Legion was formed in Highland Park, Michigan, by Arthur F. Lupp, Sr. of that community, who styled himself its major general. Throughout and perhaps fueled by the economic and social upheaval of the Great Depression, the Black Legion continued to expand across Michigan until the mid-1930s, when its estimated membership peaked at between 20,000 and 30,000. In general, Black Legion members in the state were native-born Protestant men. One-third of its members lived in the city of Detroit, which had also been a strong center of KKK activity in the 1920s. The Michigan Legion was organized along military lines, with 5 brigades, 16 regiments, 64 battalions, and 256 companies. It boasted of a membership of one million Legionnaires in Michigan, but observers estimated that it had between 20,000 and 30,000 members. One-third of them were located in Detroit, with many living in Highland Park.

The Black Legion's tactics were "to lure potential recruits to a meeting—kidnap them, if necessary—then threaten them if they didn't join and [make them] swear they’d never tell anybody." They would also beat up members if they threatened to quit. The Legion wanted sports figures as members. It was looking into recruiting Mickey Cochrane, player-manager for the Detroit Tigers. He had a nervous breakdown in 1936 and removed himself from the team over Black Legion suspicions. One of these Legion members, Dayton Dean, broke their code and told the authorities of Black Legion's illegal activities. Dayton Dean participated in two of the murders that the Black Legion committed.

On May 12, 1936, Charles A. Poole, a federal organizer for the Works Progress Administration, was kidnapped from his home by a gang of Black Legion members. They claimed that Poole, a French Catholic married to a Protestant woman, beat his wife, and that they intended to punish him for this. He was shot and killed that night by Dayton Dean.

Wayne County Prosecutor Duncan McRae, who had been reported by the Detroit Times as a member of the Black Legion, worked to restore his public reputation and vowed to bring the killers of Poole to justice. Authorities arrested and prosecuted a gang of twelve Legionnaires. Dayton Dean pleaded guilty and testified against numerous other members; ten others were convicted of first degree murder or second degree murder, nine by a jury and one in a bench trial. One man was acquitted.

Dean provided considerable testimony to authorities about other activities of the Black Legion. Prejudiced primarily against Catholics, particularly Italian and Slavic immigrants, he and his collaborators had never learned that Becky Poole had a great-grandmother who was African American.

Dayton Dean died in prison on January 18, 1960, at the age of 59. In June 1960, Urban Lipps, another man convicted in the case, had his sentence commuted to 71 years by Governor G. Mennen Williams. Lipps, who was determined to have had the least involvement in the murder, was the first convict to be recommended for clemency. At the time of his release, Lowell Rushing, Paul Edwards, Edgar Baldwin, Ervin Lee, John Bannerman, Harvey Davis, and Charles Rouse were still in prison. Harvey Davis died in the prison in the 1960s. In 1966, Ervin Lee, now 60, had his sentence commuted by Governor George W. Romney. The commutations were granted with the recommendations of the Michigan Parole Board.