A white police officer in North Charleston, S.C., was charged with murder Tuesday after shooting and killing a black man following a routine traffic stop over the weekend.

The decision to charge the officer, Michael Thomas Slager, came after graphic video footage emerged depicting Slager firing a volley of bullets into the back of Walter Scott, who was running away.

Officers rarely face criminal charges after shooting people, a fact that has played into nationwide protests over the past year over how the police use deadly force. Yet this case took a swift, unusual turn after a video shot by a bystander provided authorities with a decisive narrative that differed from Slager’s account.

“It wasn’t just based on the officers’ word anymore,” said Chris Stewart, an attorney for Scott’s family. “People were believing this story.”

Authorities on Tuesday also pointed to the video as a turning point in this case and apologized to the family for the shooting.

Samuel Scott holds a photograph of Walter Scott (R), his cousin. (Christina Elmore/Post and Courier)

“When you’re wrong, you’re wrong,” North Charleston Mayor R. Keith Summey said at a news conference. “If you make a bad decision, don’t care if you’re behind the shield … you have to live with that decision.”

[Another S.C. officer faces felony charge in separate shooting]

The Justice Department said Tuesday that the FBI would investigate the shooting along with the department’s Civil Rights division and the South Carolina U.S. Attorney’s Office.

“The Department of Justice will take appropriate action in light of the evidence and developments in the state case,” the department said in a statement.

Summey and the city’s chief of police announced at a news conference that Slager, 33, would be charged and arrested. Slager, who has been fired, was arrested by the South Carolina Law Enforcement Division, the agency investigating the shooting, and booked into the Charleston County jail shortly before 6 p.m. on Tuesday. He faces a possible death sentence or life in prison.

“It’s been a tragic day for many,” Eddie Driggers, the police chief, said at the news conference. “A tragic day for many.”

[How the shooting reignites the debate over body cameras]

The shooting began with a routine traffic stop after 9:30 a.m. on Saturday morning. After Slager stopped a vehicle, he began chasing Walter Scott, 50, and fired his Taser, according to the incident report and city officials.

The dash cam from North Charleston, S.C. police officer Michael Slager's vehicle shows the initial traffic stop and interaction that preceded Slager shooting and killing Walter Scott. (South Carolina Law Enforcement Division)

Footage of the shooting, first obtained by the New York Times and the Post and Courier newspaper, showed Scott fleeing from Slager across a tree-lined patch of grass. Slager fires a series of shots at Scott, who appears to be unarmed, striking Scott “multiple times in the back,” according to an affidavit filed Tuesday evening.

Slager told the dispatcher, “Shots fired and the subject is down, he took my Taser,” according to the portion of the report filled out by another officer who relayed what he heard.

Michael Thomas Slager (Charleston County Sheriff’s Office)

The video shows Slager picking up an item and placing it near Scott, though it is unclear if this is the Taser or something else. Police later said that Scott was hit with the Taser at least once, because part of it was still attached to him when other officers arrived on the scene. But city officials said that Scott was clearly too far away to use a Taser if he did have it.

“I can tell you that as a result of that video and the bad decision made by our officer, he will be charged with murder,” Summey said at the news conference.

After Slager shot Scott, the officer handcuffed the man’s hands behind his back and he remained there. The police report says that “several officers” gave Scott first aid, but it does not state how long it took them to administer that aid.

This shooting comes after incidents in Ferguson, Mo., and New York, among other places, have drawn heavy scrutiny over confrontations that ended with black men dead. The unrest has continued into this year, as a shooting in Madison, Wis., was followed by lengthy protests.

[How many police shootings a year? No one knows.]

North Charleston, the third-largest city in the state, has a different demographic breakdown than the rest of South Carolina. Two-thirds of South Carolina residents are white, while North Charleston has more black residents (47 percent) than white residents (41 percent), according to the U.S. Census.

But the city’s police force does not reflect that breakdown, as four out of five North Charleston officers last year were white, according to the Post and Courier. The city’s police department announced in February that it would obtain 115 body cameras for its officers after obtaining $275,000 in state funding.

Authorities stressed that the episode in South Carolina was not indicative of the city’s entire police force of 342 remaining officers, instead calling this a singular “bad decision” made by one officer.

“I think all of these police officers, men and women, are like my children,” Driggers said. “So you tell me how a father would react … I’ll let you answer that.”

[Current law gives police wide latitude to use deadly force]

Scott’s family praised the decision to charge Slager with the shooting and was “grateful” someone came forward with the video footage, an attorney said.

L. Chris Stewart, a lawyer for the family of Walter Scott, said they were aware of officer Michael Slager's arrest and questioned what would have happened if a witness to Scott's shooting had not come forward. (Reuters)

“They were sad,” Stewart, the family attorney, said in a telephone interview Tuesday evening from Scott’s mother’s home. “There is nothing that can bring their son and brother back, but they are relieved that charges were filed.”

Scott’s family members had gathered at the home on Tuesday evening, including Scott’s four children and three brothers. His family and attorneys held a brief news conference Tuesday night, saying that they planned to file a lawsuit against the city and police department.

“All we wanted was the truth, and through the process we’ve received the truth,” said Anthony Scott, Walter’s brother. “I don’t think that all police officers are bad cops, but there are some bad ones out there.”

North Charleston Mayor Keith Summey says a white South Carolina police officer will be charged with murder over the shooting death of a black man. This comes after a video surfaced which appears to show the man fleeing from the officer. (Reuters)

Slager was initially represented by David Aylor, a local attorney, who in a statement provided to local media soon after the shooting said: “I believe once the community hears all the facts of this shooting, they’ll have a better understanding of the circumstances surrounding this investigation.”

But on Tuesday, shortly before Slager’s arrest was announced, Aylor told The Post that he is no longer representing the officer.

“I don’t have any involvement in that case moving forward,” he said. “No involvement.”

[Why South Carolina indicted three other white officers in four months.]

This was the 11th time an officer has shot someone in South Carolina so far this year, according to Thom Berry, a spokesman for the state Law Enforcement Division. Berry said that the investigation into this shooting is “still very much in progress,” so he declined to comment on details of how the agency obtained the video footage.

Although officers fatally shoot and kill hundreds of people each year, only a handful of cases result in the officer facing criminal charges. Video recordings of the fatal encounters are becoming pivotal factors in whether prosecutors and grand jurors bring charges, experts said.

“Video has changed everything because it provides documentation that was never available before,” said Philip M. Stinson, a criminologist at Bowling Green State University. “Now, everyday citizens, when they recognize there is a dispute, they start recording video with their smart phones.”

However, these recordings do not always result in officers being charged. Footage of a New York City police officer placing Eric Garner in a chokehold last summer provoked widespread outrage, but the grand jury decided not to indict the officer. That decision, like that of the Missouri grand jury that did not indict the white police officer who shot an unarmed black teenager in Ferguson, sparked a national wave of protests aimed at the way African American men are treated by police.

Officials and activists in South Carolina said they were asking the community to keep calm in the wake of the video’s release and the decision to seek murder charges against him.

“We want to ask the community to remain calm,” Elder Johnson of National Action Network said Tuesday.

Watch the full video here. (Warning: Graphic content.)

Alice Crites contributed to this report.