What should be done about whites that lynched blacks in the past and got away with it?

In 1955 a 14 year old teenager named Emmett Till was burned, shot, stabbed, castrated in the state of Mississipi for whistling at a white woman. A jury in Mississipi found two men Roy Bryant and J.W. Milam not guilty of his murder and they confessed in a magazine of committing the murders. Everybody was crying over O.J. Simpson getting acquitted and now they are happy today for his sentence. Everybody loved to see Michael Vick found guilty of killing a damn dog. What should be done to those whites who lynched a million blacks from 1865 to present? Or should God just punish them after death?