Summarize what Quinn witnesses at Jerry’s

Quinn sees a policeman burst out of Jerry’s with a young Black teenager in tow. Only twenty feet away, Quinn watches as the cop beats the teenager on the ground. He has a nagging feeling he knows the boy, and with shock he realizes that the cop is Guzzo’s older brother, Paul. Quinn watches, transfixed, as Paul pins the teenager down and violently beats him up. The sound of approaching sirens pulls Quinn out of his reverie, and he runs back to Guzzo and Dwyer, who are still waiting for him in the alley.