It happened during World War II, when Aptheker, a white Jewish Communist from New York, commanded a group of black solders stationed at an Army base near Pollock, La., a town with a nasty sundown sign [a sign saying something like "Nigger, Don't Let the Sun Set on You"].
As part of their training, the soldiers were required to complete a 25-mile march. Aptheker and a black sergeant decided to march through Pollock -- at midnight.
"It was all arranged by the men," Aptheker recalled. "As we approached Pollock around midnight . . . we all began singing 'John Brown's Body' at the top of our voices -- a hundred black men with rifles and one crazy white man in front with a pistol."
From the article found here.