Ahmaud Arbery, a black man in Georgia, was just out for a run last February when, authorities say, Gregory and Travis McMichael, two white men (one of them a former police officer, as it happened), grabbed their guns, chased him down, and shot him to death. They faced no criminal penalties and were simply let off the hook until a video emerged of their attack, and public outcry forced law enforcement to act. (The two have not been asked by a judge for a plea, and attorneys for the men have told reporters they committed no crimes, according to CNN reporting.) Without the video, the wheels of justice would likely never have even begun to turn.