John L. Lewis, leader of the United Mine Workers of America, along with three other mine officials, was investigated on charges of violating Section 51 of Title 18 of the United States Code. Between 1937-1941 they were accused of conspiring to oppress employees from Mine "B" in Springfield, IL, from exercising their rights secured to them by the National Labor Relations Act. After a full investigation by the FBI, the Dept. of Justice decided not to prosecute the case and it was closed in 1943.