First we see him leaning against a wall, arms folded, a working man with pen and paper tucked into the breast pocket of his checked shirt. Then he is kneeling, removing his cap, one hand resting on a Bible as he raises the other and swears a solemn oath.

This is Wharlest Jackson, long dead and long denied justice, but preserved forever on film at the moment he takes a stand against the Ku Klux Klan. Not long after joining a Black armed resistance group in Natchez, Mississippi, the 37-year-old will be murdered with impunity.

Jackson is among dozens of forgotten victims of Jim Crow violence whose cold cases are being rediscovered, reinvestigated and retold after half a century. The process does not necessarily deliver justice or end the pain of descendants. But it does contribute, as the title of a new film puts it, to an American Reckoning.