Hundreds of protesters who minutes earlier had been dancing in the street fell silent when Kenithia Alston described the fatal shooting of her son by D.C. police.

Her voice breaking, Alston detailed a futile effort to get information about his killing and a more than year-long, unsuccessful fight to persuade Mayor Muriel E. Bowser (D) to publicly release body-camera footage. During days of demonstrations in the nation’s capital, Alston has repeatedly spoken to crowds about the 2018 death of her son, Marqueese Alston, hoping to draw attention to a lack of transparency that activists have for years decried.

“Tell this mayor to release the body cam,” Kenithia Alston said Saturday, speaking from the bed of a truck where a band had been blasting go-go music. “We got ‘Black Lives Matter’ spray-painted across Lafayette Square. Do black lives really matter?”

With the District a focal point in nationwide protests and the D.C. Council on Tuesday approving a sweeping package of police reform measures, Alston and activists are hoping the moment for change has arrived.

Among other changes, the emergency legislation unanimously approved by the council mandates the public release of body-camera video in instances in which city police use deadly force, including past cases.

D.C. police say officers fired at Marqueese Alston after he shot at them. His mother, who was allowed to view the body-camera video last year, said what she saw does not back up that account. She has long wanted the footage out in the open so people can make up their own minds.

The District’s police force was an early adopter of body cameras, launching a pilot program in 2014 in the wake of the fatal shooting of an unarmed 18-year-old man in Ferguson, Mo. By the end of 2016, the District’s 2,600 patrol officers had cameras. At the time, officials said no other city had more officers wearing cameras.

Since the rollout, there has been debate in the District and across the country about who gets to see videos from the cameras. Proponents of public release argued that it was hypocritical to adopt a program to increase transparency and at the same time block or make it difficult for the public to obtain the videos. Police said that they need to protect investigations and that the video does not always provide a full picture of events.

The law already allowed people to seek video through D.C. police or a public records request, but many were denied when investigations were in progress. The District also allows people who are in the videos to watch them at a police station.

The mayor also has had the authority to publicly release police body-camera video “in matters of significant public interest,” which has generally meant cases that generate attention or outcry.

The emergency legislation, effective immediately, mandates that after a deadly or serious use-of-force encounter involving police, footage from body cameras be publicly released within 72 hours. The legislation, sponsored by D.C. Council member Charles Allen (D-Ward 6), also requires the names of officers involved in those incidents be released.

The legislation, which includes other measures, will be in effect for 90 days, a period that can be extended for several months with a later vote. If the council wants to make the changes permanent, there will need to be a standard legislative process, to include public hearings.

“We were on the leading edge when the body-worn-camera program started, and we were very proud,” Allen said. “But five years later, a lot of other jurisdictions have passed us when it comes to transparency. It’s time for us to step up.”

“It wouldn’t have even gotten close to getting out of committee,” Allen, who chairs the council’s judiciary and public safety committee, said of the chances of such legislation passing before now. “It is only the result of so many voices speaking out and building the political will.”

Among the large departments nationwide that routinely make body-camera video public in critical police incidents are those in Baltimore, St. Louis and New Orleans. In the past week, Fairfax County police released body-camera video as they announced assault charges against an officer who used a stun gun on a man who did not appear combative.

“Why else would you have a police body-camera program if you’re not going to make it public,” said Chuck Wexler, the executive director of the Police Executive Research Forum. “If you’re not prepared to do that, then you should think twice about implementing a body-camera program.”

Bowser said at a news conference Monday that she broadly supported the legislation, but she also said officials “certainly think the body-worn-camera program works.”

Asked about complaints from families whose loved ones have been fatally shot by police, Bowser said, “I don’t know that I could agree that questions have gone unanswered.”

Marqueese Alston, who was 22 when he was killed, was living in Southeast Washington and trying to find a job, his mother said. He has a daughter, who was then 2 years old.

Kenithia Alston said she learned about her son’s death from a friend of his the night of the June 12, 2018, shooting. She said she did not hear from police until the next day, when officers told her Marqueese Alston had been involved in “an incident,” gave her the business card of a sergeant in internal affairs and a Google printout of the D.C. medical examiner’s information, according to testimony from Emily Gunston, deputy legal director at the Washington Lawyers’ Committee for Civil Rights and Urban Affairs, before the D.C. Council last year.

“This is the only communication she received from the City for almost a year,” wrote Gunston, who began working with Kenithia Alston in March 2019. “Obtaining access to this video should have been a simple task.”

It was only in August, after D.C. Attorney General Karl A. Racine (D) met with Alston, that Bowser’s office allowed Alston to watch the footage, Gunston wrote. Alston was permitted to bring three people. She declined to discuss her specific recollections of the video but said she left unconvinced of the police narrative.

She said she still does not know the names of the officers who shot her son and fears returning to the neighborhood where his daughter, now 4, still lives.

D.C. Police Chief Peter Newsham said in an interview Monday that the officers who shot Marqueese Alston have been cleared by the department. He described Marqueese Alston as a “convicted offender armed with an illegal gun who shot at a police officer.”

Two officers fired back in self-defense, the chief said, and a gun was recovered.

Marqueese Alston was on supervised release when he was killed, after serving 30 months in prison for an armed robbery.

Newsham said at the time that officers encountered Marqueese Alston during a saturation patrol effort targeting guns and repeat offenders in Ward 8, an area east of the Anacostia that has for several years led the city in homicides.

In the District, some say Marqueese Alston’s case has been ignored for too long. April Goggans, a core organizer of Black Lives Matter in the city, posted an emotional video Saturday from the protest in which she said she was “frustrated because none of these people know the names of the people who died right here.”

“For the past hour, all I can think of is watching Marqueese Alston’s body on the ground,” she said. “And Mayor Bowser has never said anything.”

Bowser did not directly address a question about Alston at a news conference where she celebrated the Black Lives Matter mural painted on 16th Street NW.

She has released body-camera video in fatal incidents involving police at least four times since 2015, including footage showing the aftermath of the shooting of Terrence Sterling, a 31-year-old motorcyclist who struck a police vehicle with his cycle while trying to elude a stop and was shot by an officer. The officer was not criminally charged but was fired by the department.

“The community just wants transparency,” said public defender Quo Judkins, who protested with Kenithia Alston on Monday.

Alston raised her first and chanted with Judkins and dozens who gathered outside D.C. Superior Court: “No justice, no peace!”

“I just want the truth,” she said. “If my son did what the chief said, why won’t they just release the footage?”

On Tuesday afternoon, Alston beamed when she learned the D.C. Council had approved the body-camera measure. She said she did not know what the next step would be for her, but she planned to call her attorney. The legislation requires the city to release the video by July 1.

“I’m like so grateful,” she said. “I feel like this is one step closer to seeking my baby’s truth.”