Emmett till was a 14 year old african american boy, when he was murdered in august 1955 in a racist attack that shocked the nation and provided a catalyst for the emerging civil rights movement. till was visiting relatives in mississippi, when he was accused of harassing a local white woman.
I suppose it made the free states and slave states in some way even. When Missouri became a slave state they kept the north end of the Louisiana purchase free stated and banned slavery there.