THE HOLOCAUST,” Stanley Kubrick once said, “is about six million people who get killed. ‘Schindler’s List’ was about 600 people who don’t.” Despite the acclaim afforded “Schindler’s List,” Steven Spielberg’s 1993 Oscar winner, its venerable dramatic strategy — addressing a tragedy of the many via the actions of a few — didn’t quite get to the heart of darkness. At least not for Kubrick.

“The Devil Came on Horseback,” which opened Wednesday in New York, has similar issues: genocide, for one. The documentary, directed by Annie Sundberg and Ricki Stern, concerns the ongoing crisis in the Darfur region of Sudan, where atrocities continue to be committed on many sides, including the rape and murder of black Africans by the Arab Janjaweed (“devils on horseback”). And it focuses on a lone hero, Brian Steidle, an ex-marine captain who served as an observer for the African Union-United Nations peacekeeping force, took photographs of the atrocities being perpetrated and eventually published them in The New York Times.

That Mr. Steidle, a white, middle-class American from a military family, is the focus of a movie about a black-African catastrophe, is something that might rankle some audiences. If there were a show of hands, Mr. Steidle’s would be the first one up.

“The hardest part for me during the filming,” said Mr. Steidle, 30, “was when we were shooting in Rwanda, during a commemoration of the genocide there. There were huge ceremonies, people crying, people lighting candles. And here’s this one camera, in the dark, with a bright, white spotlight, and it’s pointed at me, one of only about 10 white people who were there.