Mechanics at an auto repair shop in Greenville, S.C., were toiling on a busy summer afternoon last month when they heard a commotion outside. According to Nick Simmons, the shop manager, someone was shouting, “Stop resisting!” while another voice asked, “What did I do?”

The workers were overhearing the arrest of Zebbie Hudgens, a 56-year-old Greenville man, by five deputies from the Greenville County Sheriff’s Office. On Tuesday, Mr. Simmons described how a violent encounter on Aug. 1 that began with a few witnesses in a parking lot had been thrust before an ever-widening audience, leading to an investigation and the firing of one of the deputies.

“We ran to the door to see what was going on,” Mr. Simmons said in an interview, describing how he and about nine co-workers at Simuns Tire watched from the bays. “Within 15 seconds, he was being held down by five officers. He kept saying: ‘What did I do? What did I do?’ They were really not answering him at that point in time.”

Image Zebbie Hudgens Credit... via Traci Fant

As Mr. Simmons and his co-workers looked on, the shop’s surveillance cameras were trained on the lot . The recordings show Mr. Hudgens with his arms outstretched, backing away as a deputy charged him and then threw him to the ground.