S7·E10 Shades of Gray

A white bus driver striking a black female pedestrian sparks a riot. The driver is killed, and some distance away from the riot another body is found. MGee and Gharty look into the death of the driver while Lewis and Sheppard look into death of the other body. Lewis finds a clue at the scene, a button (later discovered to be missing from a police uniform). Gharty and MGee actively debate whether race was the motivation for the driver's beating death; MGee suspects the incident wasn't racially motivated. The bus riders are interviewed to find out what they know. Lewis and Sheppard approach a house looking for their witness (without backup). For her trouble Sheppard keeps hold of her suspect, but loses her gun and is severely beaten. Ballard is recalled from her hiking vacation. Lewis lays down the law for the residents of ""Little Jamaica""; he wants Sheppard's gun returned tonight. The witness Sheppard caught identifies Hellriegel as the murderer, and the men who beat the driver to death