HOOVER, Ala. — After gunshots rang out in a cavernous suburban shopping mall on Thanksgiving night, Ashlyn McMillan encountered a man she considered a hero. He directed frantic shoppers to safety, hand on his gun to defend against a looming threat. “Get down,” Ms. McMillan recalled him saying. “Go in the store.”

Yet to a police officer who raced to the scene in Hoover, Ala., the black man with the gun was not a hero in action, but “a suspect brandishing a pistol,” according to a police account. The officer fired at him, and the man, Emantic Fitzgerald Bradford Jr., died.

As it turned out, Mr. Bradford was not the gunman the police had been searching for. On Thursday, police arrested someone else — Erron Martez Dequan Brown, 20, and charged him with attempting to murder an 18-year-old man who was shot during the melee.

The correction was too late for Mr. Bradford, whom the police initially identified as the culprit, only to change their story a day later. Mr. Bradford had not shot anyone, the Hoover police said, but was a licensed gun owner at a chaotic scene in the crowded mall.