NORTH CHARLESTON, S.C. — The mayor of the South Carolina town where a white officer was filmed fatally shooting an unarmed black man called the incident a “horrible tragedy” as he announced that  all patrol officers would be outfitted with body cameras.

“There have been two families that have been harmed greatly by what occurred — both the victims’ and the officer’s family — and our hearts go out to both of them,” North Charleston Mayor Keith Summey said during a Wednesday news conference.

Michael Thomas Slager, a former North Charleston police officer, was arrested and charged with murder Tuesday for shooting and killing Walter Scott during a traffic stop three days earlier.

Slager, 33, initially said after the shooting that Scott had taken his Taser during a confrontation  Saturday morning; but graphic video footage released Tuesday showed that Scott, 50, appeared to be unarmed when he ran away. In the footage, Slager is seen firing a volley of shots at Scott’s back, and a criminal affidavit says that he struck the man “multiple” times.

Police Chief Eddie Driggers said Wednesday that he was “sickened” by the footage.

Wednesday’s news conference turned chaotic at times, as protesters interrupted officials with chants of “No justice! No Peace!” and demanded that Driggers answer questions about the investigation, which is being handled by the South Carolina Law Enforcement Division. The FBI has also said it is investigating the incident.

Summey and Driggers declined to answer specific questions regarding the incident, noting that SLED, and not the city, is leading the investigation. But Summey said Wednesday that he has not “seen all of the video,” which was recorded yards away from the shooting by a bystander who turned it over to the Scott family.

The mayor and the chief said they visited with Scott’s family Wednesday morning and pledged a police escort for his funeral.

Summey called them “a wonderful, down-to-earth family, a wonderful group of people, and we let them know how we felt about their loss and how bad it was, and we do not condone wrong. It doesn’t matter who it is. And we are there to support them as we can for the future.”

Said Driggers: “I have been praying for peace for the family and peace for the community.”

SLED officers arrested Slager on Tuesday and booked him into the Charleston County jail. Slager has been fired from the police force, but Summey said Wednesday that Slager’s wife, who is eight months’ pregnant, will remain on the city’s health insurance plan until after she delivers her baby. “We think that’s the humane thing for us to do,” he said.

The additional body cameras were ordered Wednesday morning, which would add to the 115 already secured through a federal grant. But Summey cautioned that it could take some time before officers would be patrolling with them, as they need to be trained and the department needs to finish drafting its policy surrounding their use.

Scott’s family praised the arrest  Tuesday evening, with an attorney saying they were “relieved” that charges were filed.

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

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.

A few dozen protesters showed up outside the North Charleston city building  Wednesday carrying signs and crying familiar chants.

“We’re out here for justice, we’re out here because black lives matter,” said Jeremy Johnson, a 21-year-old who has lived in the town for three years.

Johnson said he was appalled, but not surprised, by the video showing Scott’s killing.

“This is not just about justice for Charleston. It’s about justice for Mike Brown, it’s about justice for Eric Garner,” Johnson said. “It’s about justice everyone.”

The protesters — vocal but relatively small in number — insisted that the shooting was symptomatic of bigger and deeper problems in local policing. But they insisted that demonstrations must remain peaceful.

“The system is our enemy — not these individual officers,” said Pastor Thomas Ravenell. “We cannot change the law by breaking the law.”

Former governor Mark Sanford (R), now a U.S. congressman whose district includes parts of North Charleston, stopped by the demonstration and spoke with local ministers about the shooting, which he called “unfathomable.”

Sanford said it was too soon to discuss legislative fixes — such as body cameras and policing reform — but praised local officials for swiftly charging the officer.

“As the mayor said, right is right and wrong is wrong,” said Sanford. “We all live with the decisions that we make. And so will this officer.”

Mark Berman contributed. Lowery reported from North Charleston. Izadi reported from Washington.