A Georgia police department has fired one of its officers less than 24 hours after he was caught on video kicking a handcuffed man in the head during a traffic stop.

Robert McDonald was fired from his position as master police officer by the Gwinnett County Police Department on Thursday, the department said in a press release.

McDonald was the second officer on the scene of a traffic stop in Lawrenceville, near Atlanta, on Wednesday. He can be seen on video running toward the suspect, Demetrius Hollins, 21, who was handcuffed and being held down on the ground by another officer, and then kicking him in the head.

“Robert McDonald stepped outside of the guiding principles of our agency and as a result of his actions he was terminated less than 24 hours after the incident occurred,” Corporal Deon Washington said in a statement. “The actions by this former officer do not represent the officers of this department who dedicate their lives to serving the community on a daily basis.”

Gwinnett County Police Chief Butch Ayers said the video, “disturbed me, as it disturbed everyone who actually witnessed that video. … What happened yesterday at the hands of one of my former officers was embarrassing not only to the Gwinnett County Police Department, but to all law enforcement. We hold our officers accountable for their actions and in less than 24 hours the Gwinnett County Police Department held this officer accountable.”

Here’s what you need to know:

1. The Chief Says McDonald, Who Was Responding to a ‘Tense Situation … Basically Got Tunnel Vision & He Acted Inappropriately’

Former Master Police Officer Robert McDonald was responding as backup to a traffic stop on April 12 involving Sergeant Michael Bongiovanni, who had stopped Demetrius Hollins for driving without a license plate.

The incident occurred about 4 p.m. at the intersection of of Sugarloaf Parkway and Lawrenceville Suwanee Road in Lawrenceville, according to police.

Police said Hollins made lane changes without signaling while being followed by Bongiovanni. He slowed down, but continued on for about a 1/4 of a mile, police said. Bongiovanni said he smelled the odor of marijuana when he approached the car.

A video recorded by a bystander shows Bongiovanni pulling Hollins out of a car after a “struggle” between the two. He then handcuffs him. Police said Bongiovanni used a Taser on Hollins during the struggle.

McDonald arrives on the scene and runs toward the other officer and Hollins, immediately kicking Hollins in the face as is on the ground in handcuffs.

“The man in that video was lying down, he was clearly handcuffed, he was clearly not resisting and was not a threat to anyone,” Chief Butch Ayers said at a press conference. “He was responding to a tense situation as a backup officer. Once he got there, he immediately proceeded and basically got what I would call ‘tunnel vision.’

“He acted inappropriately, outside of policy, he did something we don’t teach in our academy and he was held accountable for it,” Ayers said.

Chief Butch Ayers: "What I viewed on that video was disturbing and embarrassing. The officer got tunnel vision." @GwinnettPd @FOX5Atlanta pic.twitter.com/GAhhlHnyfQ — Portia Bruner (@PortiaFOX5) April 13, 2017

He said the officer was winded, and may have needed help, but the use of force was uncalled for.

Ayers said when he watched the video he was “mad … upset, and it felt like I was gut punched. I tell these officers when they graduate from the academy that I want them to treat citizens the way they would want another officer to treat a member of their family.”

He said there are times when use of force is justified, like resisting arrest, but in this case, “he was on the ground, handcuffed, any further application of force was unnecessary and excessive. It hit us to the core.”

Bongiovanni remains on regular duty and is not under investigation, authorities said.

Chief Ayers is giving a press conference now in reference to Ofc. McDonald's actions yesterday. Behind him is the GCPD Command Staff. pic.twitter.com/LaSSXYQP02 — Gwinnett Police Dept (@GwinnettPd) April 13, 2017

Ayers said Bongiovanni learned at the scene that the use of force may have gone outside policy. He contacted the on-duty shift commander, who initiated an investigation, prior to police learning about the video.

“The officer was placed on administrative leave, his department issued firearm was taken, and he was sent home,” police said in a press release. He was fired the next day.

2. A Mugshot From the County Jail Shows Hollins With a Bloodied Nose & Lip After His Arrest

A mugshot of Demetrius Hollins released by the Gwinnett County Jail shows the 21-year-old was left with a bloodied nose and lip after the incident.

Acocrding to the arrest warrant, which was obtained by ABC News, Bongiovanni claims Hollins “did knowingly and willfully obstruct or hinder” him while he was trying to make an arrest and ignored “verbal commands to exit (his) vehicle and then (refused) to place hands behind his back after he was told he was under arrest.” The warrant also accuses Hollins of “physically” resisting arrest.

He was stopped because he didn’t have a license plate and the passenger side brake light was out in his red Acura Integra, the police report states. Sergeant Bongiovanni wrote in his report that Hollins “began to act strange,” and was yelling “I need to call my mom” and “you have to let me go.”

Bongiovanni said he smelled marijuana in the car and recognized Hollins from an August 2016 arrest in which he took Hollins into custody on charges he had marijuana and a loaded gun in his car. Bongiovanni then called for backup and continued to order Hollins to exit the car, according to the report.

“Hollins turned away from me and I feared he would reach for a weapon or try to start the vehicle and drive off. In my previous encounter, he reached for a loaded firearm that was under his seat,” Bongiovanni said in the report obtained by ABC News.

Bongiovanni said he pulled Hollins out of the car and after a struggle and multiple uses of his Taser, was able to detain the 21-year-old suspect.

It was then that McDonald arrived on scene as backup and kicked Hollins in the head, an action police have deemed to be excessive.

An ambulance was called for Hollins because a Taser was used on him. He was later booked into the Gwinnett County Jail and released Thursday after posting $7,500 bail.

He is facing charges including obstruction of a law enforcement officer, failure to signal, having a suspended or revoked registration, possession of less than an ounce of marijuana and driving with a suspended or revoked license.

Demetrius Hollins released from Gwinnett Jail. $7,500 bond posted at noon. Chief to comment about officer soon.

@FOX5Atlanta @GwinnettPd pic.twitter.com/CZosUJRXBq — Portia Bruner (@PortiaFOX5) April 13, 2017

His attorney told reporters the officer’s firing is a “good start” by authorities.

“There’s a lot more to this and we just want to get him squared away and make sure he’s OK first,” attorney Justin Miller told reporters.

Miller said he would be taking his client to the hospital for evaluation.

“All I can say is I wish this never happened to me,” Hollins told reporters after his release from jail.

3. McDonald Told His Former Chief He Is ‘Sorry It Occurred’ & for the ‘Embarrassment to Himself, to the Agency & That It Shouldn’t Have Happened’

Police Chief Butch Ayers said Robert McDonald took full responsibility for his actions.

McDonald told Ayers he is “sorry that it occurred. And the embarrassment to himself, to the agency and that it should have happened,” the chief told reporters.

“This incident, this type of force and this action was uncalled for,” Ayers said. “There is no excuse for it. We have taken appropriate and swift action to deal with this. This officer and his actions do not represent the men and women who put their lives on the line everyday to protect this county.”

Ayers said, “We hold our people accountable. It was the sergeant that initiated the follow-up. We didn’t delay, we didn’t try to say this is pretty, or something that it wasn’t. This was definitely uncalled for, unnecessary, an excessive force and we dealt with it.”

McDonald has not spoken publicly about the incident and it is not clear if he has hired an attorney.

4. McDonald Was Hired in 2013 & Was Involved in 2 Prior Use of Force Incidents

Presser on officer caught kicking handcuffed man in GwinnettGwinnett County Police Chief is speaking about the officer that was fired after he was caught on camera kicking a handcuffed suspect in the head Wednesday afternoon. 2017-04-13T20:02:49.000Z

Master Officer Robert McDonald was hired in 2013 and began working in the field in August 2014 after graduating from the police academy, WXIA-TV reports.

He was involved in two previous use of force incidents, the news station reports:

In the first, which happened April 19, 2015, McDonald was assisting another officer in an aggravated domestic dispute call. Another officer deployed her Taser on a man who was allegedly not responding to verbal commands. McDonald placed his knee in the man’s back while other officers handcuffed him. In the second incident, which took place on September 15, 2016, McDonald deployed his Taser on the passenger of a vehicle who was allegedly attempting to flee the scene after being pulled over on a traffic stop. The suspect received a cut to his face as he fell to the ground.

He was also involved in two motor vehicle crashes during his three years as an officer, according to WXIA. He was found not at fault in a May 2014 crash.

But he was found at fault in July 2015 when he rear-ended a teen driver’s car. He claimed the teen came to a sudden stop and didn’t use a turn signal, but a review found he was following too closely. He lost his “good driving record” and privilege of taking his vehicle home.

McDonald had a recent performance evaluation in August 2016, and was rated as “often exceeds expectations” in 12 categories and “generally meets expectations” in the other six.

“Up until what occurred yesterday he had no citizen or internal complaints,” Ayers said. “Anytime an officer uses force in the Gwinnett County Police Department, they’re required to complete a use of force report.”

Ayers said that report goes up the chain of command for review, all the way to him, and it is then given to professional standards for record keeping.

“The mere fact there were 3 or 4 uses of force does not indicate there was anything improper with those prior uses of force,” Ayers said.

According to WXIA, he received a “Good Conduct 3 years ribbon” in 2016 given to those who “have exhibited good conduct for a three-year period with no disciplinary actions (excluding auto accidents and verbal counseling).”

5. The Police Department Will Conduct a Criminal Investigation & the District Attorney Will Decide if McDonald Will Face Charges

Video shows Gwinnett cop stomp handcuffed man's headA Gwinnett County police officer is under investigation after video of a traffic stop shows him stomping a handcuffed man in the head. (http://on.11alive.com/2nIH7qb) 2017-04-13T14:28:11.000Z

The Gwinnett County Police Department will conduct a criminal investigation into the former officer’s actions and will then turn the case over to the local district attorney’s office, authorities said.

The district attorney will decide if McDonald will face charges.

“What happened yesterday was clearly outside of state law and department policy. We do not tolerate actions that are not consistent with our core values or state law,” police said in a statement.

Police Chief Butch Ayers told reporters an external agency, like the Georgia Bureau ofInvestigation, will not be brought in to investigate at this time.

“The history of this department is we investigate our own people and we have held our own people accountable,” Ayers said. “You can go back through time and find where officers within this department have actually been arrested by the Gwinnett County Police Department. We have not had to rely on external agencies to come in.”

Ayers said “the video speaks for itself. I don’t think there’s any need to bring an outside agency in. The Gwinnett County Police Department has dedicated, professional and honest investigators that will and have conducted the investigation.”

The chief said he hopes the police department and community can move forward.

“We recognize that the trust between the community and law enforcement is fragile,” Ayers said. “And situations like what occurred yesterday only make things worse. Therefore, it was extremely important that the Gwinnett County Police Department do a thorough, quick and honest evaluation as to what occurred and to take appropriate action.”