Many in San Francisco’s African American community remember well when they first heard that five city police officers had shot and killed Mario Woods in the Bayview neighborhood.

But one year later, they recall more clearly the moment, that same day, when they saw the first of two smartphone videos of the shooting. That’s when they understood the incident would draw San Francisco into the turbulent national conversation about police accountability — that it would represent both a tragedy and a turning point.

“It wasn’t until the crisis came that those who had not been involved got involved and started listening and started talking,” said Rev. Amos Brown, president of the San Francisco chapter of the NAACP. “It’s unfortunate that it takes that.”

Shawn Richards, founder of the nonprofit Brothers Against Guns, was across town in a class at San Francisco State when his phone started blowing up that day. “Someone just got killed on Third Street,” his friends messaged him. Later he drove to the scene, and as he pulled up, he received a text including the video.

“When you have something on film like that, you can’t ignore that,” Richards said. “You just can’t.”

City attorneys have defended the shooting in court papers, saying the officers who killed Woods on Dec. 2, 2015 — after failing to subdue him with pepper spray and beanbag rounds — used lawful self-defense on a stabbing suspect who still had a knife, refused to obey commands and was under the influence of methamphetamine.

But while city prosecutors continue to investigate the case, there’s no denying its power. One year later, the image of the 26-year-old Woods staggering along a sidewalk, then falling as five officers open fire and strike him at least 20 times, is imprinted into the psyche of the city, from its dwindling black population to community organizers to law enforcement leaders and politicians.

The image spread far. Black Lives Matter activists got a “Justice for Mario Woods” sign into the hands of Beyoncé’s backup dancers after their Super Bowl performance at Levi’s Stadium, and the clip of the women in Black Panther berets holding up their fists in solidarity was shared worldwide .

Moreover, the Woods case thrust the black community’s struggles and its frayed relationship with police into the spotlight, becoming the force behind unprecedented police-reform efforts — the success of which remains to be seen. It contributed to Police Chief Greg Suhr’s resignation in May, and shadows the ongoing search for a new chief.

Woods’ death resonated for many reasons, among them that video showed Woods did not appear to directly threaten officers before he was shot. It also highlighted problems in the way city authorities investigate such cases, with the Police Department assuming the lead.

Even Woods’ troubled background — he had spent years in prison; his family said he had mental health issues — was seen by many community leaders and activists not as a mitigating factor explaining his death, but another reason to push for deep change.

“The community has used this as a rallying cry to go beyond the death of Mario, to also talk about his life and how his plight is symbolic to the plight of all African Americans in San Francisco, in being under the constant threat and danger of police action,” said Adante Pointer, one of the attorneys representing Woods’ family in a federal civil rights lawsuit against the city.

“In Mario’s life, as well as his death, you see black San Francisco in a lot of ways,” Pointer said. “As a result of the tragedy, you have black San Francisco rallying around his death in order to make the future better ... so that they don’t see their sons and daughters go through a similar path.”

The police force had already been embroiled in its share of disputed shootings and race-related scandals. A federal corruption investigation into warrantless searches conducted by plainclothes sergeants had turned up a series of racist and homophobic text messages sent between 14 officers.

But then came the Woods video, which was posted on social media as the city’s Police Commission met. During a recess, members of the public played it on repeat, the sounds of the gunfire echoing through the chamber.

Monroe Whitt, Mario Woods’ older brother, recalled hearing about the shooting as he rode Muni to a new security job. But it was the video that made his brother’s death real.

“It was the sounds — the pow-pow-pow-pow,” said Whitt, 35. “I was in the car with my cousin at the vigil (the next evening), and she made me watch it. I wasn’t ready to watch it, but that was when everything hit.”

Within a week, the commission reopened the Police Department’s use-of-force policy for the first time since 1995, citing the need to put more of an emphasis on de-escalation.

Mayor Ed Lee and others asked the U.S. Justice Department to open a collaborative review of the city force that, months later, “found a department with concerning deficiencies in every operational area assessed.” Lee has pledged that every reform suggested by the Justice Department will be enacted.

In September, District Attorney George Gascón and the mayor’s office said they were working on a plan to give Gascón’s office the lead in police shooting investigations, which could ease concerns about cops policing themselves.

“Before the shooting, the (mayor’s) African American Advisory Board was already in place, and we told them, we need to discuss racial profiling, we need to discuss police conduct in black neighborhoods,” said Richards. “We had already brought those discussions up but they were ignored. When this happened, they got put on the forefront of things we need to do.”

Interim Police Chief Toney Chaplin said this week that the department has undergone “significant changes” since Woods’ death. He said, though, that he believes these changes would have happened even without the shooting.

“When the spotlight hit, it was hitting everywhere in the country,” Chaplin said. “There may be an argument that San Francisco felt kind of shielded until Mario Woods, but once that happened, it pushed us right into the national conversation with everybody else.

“There’s a lot of training we have to roll out nationwide,” Chaplin said. “San Francisco is on the cutting edge of it, and we’re going to continue being on the cutting edge of it.”

Some reforms have seemed to stall. For instance, the Police Department’s new use-of-force policy is tied up in negotiations with the police union. But Supervisor Malia Cohen, who represents the Bayview, said San Francisco as a whole seems more aware of the problems black people have experienced for generations.

Cohen pointed to the recent success of a ballot measure she authored that will strengthen San Francisco’s civilian police oversight agency. More than 80 percent of voters approved it.

“That’s across the city — that includes communities who think it’s a black problem and not their problem,” Cohen said. “I think in one year’s time, we have changed the cultural norm. We have an environment now to usher in change.”

While many in the black community agree that the shooting sparked a movement, some say real change has yet to come. Archbishop Franzo King, of Saint John Coltrane African Orthodox Church, noted that the city District Attorney’s Office has never charged an officer in a fatal shooting. The way to shift the culture of a police department, he said, is to bring consequences.

Woods’ death did cast two later shootings in a new light. After police killed a homeless man named Luis Gongora in the Mission District in April, the department faced scrutiny over whether officers had sought to de-escalate the confrontation. And after an unarmed car-theft suspect named Jessica Williams was shot and killed in May, Suhr stepped down. Both shootings remain under investigation.

“The call is for justice,” King said. “I do believe that if in fact Mario Woods’ killers had been arrested, that Jessica Williams would still be alive.”

Whitt, Woods’ brother, hopes the officers are charged. However, he also believes that “progress is happening now, on minute levels but on levels nonetheless.”

He said his brother had been trying to get back on the right path when he was killed. Though he’ll never get to see who Woods might have become, Whitt said it’s not surprising his brother is part of a bigger story.

“I think it’s a testament to who he was,” he said. “He was a live wire. He was a spark plug. It’s unfortunate that this had to happen, but the light has been shined on law enforcement. Everything happens for a reason, and for that my brother Mario will always be known.”

Vivian Ho is a San Francisco Chronicle staff writer. Email: vho@sfchronicle.com

Twitter: @VivianHo