In 1964 a mob of Mississippians killed three civil rights workers who’d come to the state to register local blacks on voting rolls. The documentary Neshoba shows that it took decades for any sort of justice to be meted out; ringleader Edgar Ray Killen was convicted in 2005. It’s somewhat satisfying to see the unrepentant old racist rolled off to jail in a wheelchair, but interviews with local people suggest that the hateful attitudes that fueled the murders persist. “Let sleeping dogs lie,” says one man—but the filmmakers, by retelling this sordid tale, are quite willing to wake the beast and do battle with it.