The second video gained traction after it was posted by a Twitter account called @GaFollowers. It was unclear who originally shot the video.

“The revelations uncovered in this entire investigation are shocking,” police department spokesman Cpl. Deon Washington said in a news release. “We are fortunate that this second video was found and we were able to move swiftly to terminate the supervisor who lied and stepped outside his training and state law.”

Bongiovanni did not mention the punch or any use of force in his incident report or in subsequent interviews with investigators, police Chief Butch Ayers said.

Bongiovanni was hired in 1998 and graduated from the police academy in February 1999, police said. The sergeant’s personnel file was not immediately available.

A criminal investigation has been launched into Bongiovanni's actions, as well as those of McDonald. Before news of Bongiovanni's termination spread, Gwinnett County District Attorney Danny Porter said he "anticipated" there being criminal charges filed against his colleague.

“We acknowledge that the actions of these two officers have implications that will be felt for some time,” the department’s final Thursday night news release said. “However, we also believe that our decisive action in terminating both officers speaks volumes about what is expected of each officer that wears a Gwinnett County police badge.”

A video posted to social media appears to show a Gwinnett County police officer kicking a man in the head as he lies on the ground during a traffic stop. Video credit: Kent Jones.

The incident unfolded shortly after 4 p.m. Wednesday when Bongiovanni tried to initiate a traffic stop near Sugarloaf Parkway and Lawrenceville-Suwanee Road.

The red Acura Integra driven by 21-year-old Demetrius Bryan Hollins did not have a license plate, and Hollins changed lanes multiple times without signalling, according to an incident report. Hollins’ did not immediately pull over, but his car eventually stalled out.

According to Bongiovanni’s report, the car smelled of marijuana and Hollins “began to act strange,” saying he wanted to call his mother. Bongiovanni asked Hollins to get out of the car and he resisted, the report said.

Bongiovanni eventually Tasered Hollins, pinned him on the ground and handcuffed him.

That’s when the roughly two-minute cellphone video captured by bystander Kent Jones starts.

Bongiovanni struggles briefly with a screaming Hollins before bringing him under control. About 45 seconds into the video, McDonald is seen jogging into the frame, barely slowing down before stomping on Hollins’ face.

“You’re supposed to protect and serve,” Jones told The Atlanta Journal-Constitution on Thursday. “That’s not protecting and serving right there. That’s brutality all day.”

Before the new video of Bongiovanni surfaced, Ayers said McDonald had been called as back-up after the suspect initially resisted arrest but that, by the time he arrived, the situation was largely under control. McDonald, said the police chief, was not.

“He was responding to a tense situation… and basically proceeded to get what I call tunnel vision,” the chief said. “He did something we don’t teach in our academy.”

Jones’ video ends as Hollins is placed on the trunk of his car.

Hollins was ultimately charged with possession of less than an ounce of marijuana and obstruction of a police officer as well as several traffic citations, including driving on a suspended or revoked license, operating a vehicle with suspended or revoked registration, failure to signal and “brake lights required.”

His bloodied nose and lips are clearly visible in his mug shot.

“All I can say is I wish this never happened to me,” Hollins told Channel 2 Action News after he was released from jail.

Read more about the incident, its fallout and community reaction at myAJC.com.