Brown said Corey has appeared on the "Ellen DeGeneres Show" and recently toured with J. Cole, Young Thug and Jaden Smith.
The department did not release the name of the officer, who is still on active duty, citing a pending investigation.
The video, which contains explicit language, starts with the officer holding the boy by the arm. It is unclear how the confrontation began.
“You’re 12?” the office is heard asking the boy. “You’re about to go to jail. You’re going to go to a youth detention center if you don’t (inaudible).”
A woman, who later identifies herself as Corey’s aunt, can be heard off-camera defending him.
“I have his father on the phone and you won’t even speak to him,” she said to the officer.
“Yup,” the officer replied.
The camera is jostled as an apparent altercation breaks out and the video ends with the officer calling in the incident as another officer restrains the boy. It has been viewed thousands of times and drew heated criticism from some corners.
"Look how this officer (is) touching this young kid," filmmaker Jason Pollock wrote when he shared the video on Twitter Monday. "He would never be treating a little white kid like this."
Register said there was more to the story than what is seen in the video, saying that Corey had recently been issued a criminal trespass warning for selling CDs at the mall. Register said security saw him again and called the Cobb officer, who was working part-time for the mall.
When the officer arrived, Register said Corey was “verbally combative,” refused to answer questions and then made to leave, at which point the officer “got physical control” of him.
Register said Corey “pushed or swung at” the officer and then his aunt “physically attacked” him. Eventually, they were both taken into custody, and the child was released to his father, who was also at the mall that day.
Register said Corey is being charged with felony obstruction and misdemeanor criminal trespass and disorderly conduct. His aunt is being charged with felony obstruction and misdemeanor criminal trespass, disorderly conduct and providing a false name to law enforcement, according to Register.
Register said charging the child with a felony was at the discretion of the officer.
The incident is not the first time Cobb County police have come under scrutiny. A 2017 study by the International Association of Chiefs of Police found the department plagued by "perceptions of racism," although the study said it found no evidence of discrimination.
Just a few months later, though, a lieutenant was allowed an immediate retirement after he was caught on camera telling a motorist, "We only kill black people, right?"
Since then, Register has won some praise from advocates for measures he has taken to emphasize community policing, but those same measures drew disdain from some in his own department.
On Tuesday, Register promised a full investigation and expressed concern that the incident would further damage community-police relations.
“We’re in this together, and we’ve got to work together,” he said.