I used to work at a local mall, Marketplace Mall to be exact. It was common to see shoplifting suspects being brought down from out in the mall for questioning. One night, and it was a classic cop scenario, some black guy was brought into the security office. I was in the break room beside the office when I heard the cop, and the suspect, arguing. It got loud and vocal and then I heard a thud so loud that I thought the wall was going to explode.
Later what I was told was that the cop, a white deputy from Monroe county NY, had responded to the suspect after he said something like "I know you. You're not so tough". What I heard was that the deputy had whacked the suspect's head with a baton, cracking it open and leaving him bleeding. They let the suspect leave. There were mall security people present and no one said anything apparently.