What began with an attempted traffic stop ended some 26 hours later with two Gwinnett County police officers fired for stomping and punching a black motorist.

The brutal encounter, captured on separate cell phone videos, left the county - the most diverse in the state - reeling on Thursday. Both officers are white.

“The revelations uncovered in this entire investigation are shocking,” Gwinnett police said in a statement released late Thursday.

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The dizzying chain of events began shortly after 4 p.m. Wednesday when Gwinnett police Sgt. Michael Bongiovanni tried to initiate a traffic stop near Sugarloaf Parkway and Lawrenceville-Suwanee Road. The driver, Demetrius Bryan Hollins, did not have a license plate and changed lanes multiple times without signaling, according to an incident report. Hollins’ did not immediately pull over, but his car eventually stalled out. Bongiovanni was joined at the scene by Master Police Officer Robert McDonald.

A cell phone video posted on Twitter soon after the stop showed McDonald stomping on Hollins’ head as he ran up to the scene. Hollins was handcuffed and prone at the time.

Moving quickly, police fired McDonald Thursday afternoon.

“The suspect was lying down, he was clearly handcuffed, he was clearly not resisting,” Gwinnett County Police Chief Butch Ayers said at a news conference. “He wasn’t a threat to anyone. Any further application of use of force was unnecessary and excessive.”

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.

At that same news conference, Ayers commended Bongiovanni for following protocol and reporting the stomping incident by McDonald to his shift commander.

But then, just hours later, a second video surfaced on Twitter which showed Bongiovanni soon after the stop punching Hollins, who had both hands up.

“The video was contrary to what was reported by Michael Bongiovanni,” Gwinnett police said in a statement. “We are fortunate that this second video was found and we were able to move swiftly to terminate a supervisor who lied and stepped outside of his training and state law.”

Ayers said Bongiovanni didn’t mention punching Hollins in his incident report or in a subsequent interview.

“One thing that we will not tolerate in this police department is providing false or misleading information,” Ayers told reporters late Thursday.

McDonald and Bongiovanni, hired by Gwinnett police in 1998, are under internal investigation.

Criminal charges are likely, at least for McDonald.

“Based on what I know right now, I would anticipate there are going to be charges,” Gwinnett County District Attorney Danny Porter said Thursday, before the video of Bongiovanni surfaced. “But I don’t know what they are yet.”

The first video was shot by Kent Jones, who just happened to be driving in the area, shot that video. He posted it on his Facebook page and it has been viewed tens of thousands of times.

“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.”

McDonald, a three-year veteran of the force, was placed on leave “immediately” after the Wednesday afternoon incident near Lawrenceville, officials said. His termination — and the launch of a criminal investigation into his actions — were announced by 1 p.m. Thursday. The chief said the probe into McDonald’s behavior was launched even before cellphone video of the incident gained traction on social media.

The incident comes at a time when racial tensions in Gwinnett have been strained after a county commissioner called Congressman John Lewis a "racist pig" on Facebook. But, even in a national climate where police-involved incidents garner extra scrutiny, Gwinnett's police department has largely avoided headline-grabbing incidents.

In a statement, the department acknowledged “the actions of these two officers have implications that will be felt for some time. 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.”

‘Covered in blood’

Bongiovanni had arrested Hollins before, according to Ayers. In his report, Bongiovanni said Hollins’ car smelled of marijuana and he then “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.

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

That’s when Jones’ roughly two-minute cellphone video starts.

Demetrius Hollins

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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.

“His face was covered in blood,” Jones said.

Ayers said McDonald had been called as back-up after the suspect initially resisted arrest but 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.”

The video ends as Hollins is placed on the trunk of his car. He 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.

‘A signal to the community’

Last August, McDonald was honored for three years of “good conduct” with the Gwinnett County Police Department. He was one of several department members named “Officer of the Month” in November 2015. Before Wednesday’s incident, he had used force three times — once in 2015, once in 2016 and once this past February — but none of those incidents resulted in any citizen complaints.

Ayers said Thursday that McDonald had taken responsibility for his actions and was sorry that they occurred.

Bongiovanni, said Ayers, offered no apologies. His personnel file will be made available Friday, police said.

“It’s different out on the streets,” Bongiovanni told Ayers.

It was unclear if either officer had hired an attorney.

Dunwoody police Chief Billy Grogan, the president of the Georgia Association of Police Chiefs, called Gwinnett’s actions “swift and just.” Gwinnett County Commission Chairman Charlotte Nash and County Administrator Glenn Stephens also praised the decision.

Gwinnett County police officials hold a news conference to discuss the firing of an officer who stomped the head a handcuffed man. CHRISTIAN BOONE/AJC

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“Their actions send a signal to the community, the department and to the nation that the conduct reflected in the video will not be tolerated,” Stephens said.

Some activists, however, said the terminations don’t make the actions any less jarring.

Tiffany Williams Roberts, an organizer and attorney for Black Lives Matter of Atlanta, said the incident embodied “the kind of terror that black people deal with on a daily basis.”

The Georgia NAACP, before Bongiovanni’s video had gone public, said it was “disgusted” by McDonald’s actions.

In a statement from President Francys Johnson, the organization referenced U.S. Attorney General Jeff Sessions’ recent memorandum ordering the Department of Justice to review its police reform efforts.

“The NAACP has historically pushed criminal justice reform efforts including reforms that promote accountability in policing,” Johnson’s statement said. “I hope police departments are not taking their cue from the Trump administration that it’s okay to go back to the old ways.”