MEMPHIS — The body cameras worn by the Memphis police officers who stopped Tyre Nichols recorded his anguished cries and the conflicting orders that were virtually impossible for him to obey. As the officers punched and pepper-sprayed him, though, those cameras were often jostled, pointed away or dark.
But the residential street where the officers had caught up with Mr. Nichols after he ran from them on the night of Jan. 7 happened to have another camera trained on it, affixed to a utility pole in a white metal box with a bright blue light.
It was one of the hundreds of SkyCop cameras, as they are known, that the Memphis Police Department has installed around the city. It was watching from above, recording as Mr. Nichols was beaten and then as officers and medics delayed providing aid. He died three days later.
“Glory be to God that a SkyCop camera was there to catch what happened,” Van D. Turner Jr., the president of the Memphis branch of the N.A.A.C.P., said last week.
The overhead footage, publicly released on Friday along with some of the officers’ body camera videos, has been widely regarded as critical in shaping the public’s understanding of what unfolded after the police pulled over Mr. Nichols that night, by offering an unobstructed bird’s-eye view.
Camera systems like SkyCop, which have been adopted by police departments around the country, have been criticized by activists and privacy advocates as a costly investment that does little to deter crime while adding to the overbearing presence that the police often have in neighborhoods — especially poor ones — where the cameras have proliferated.
Yet in this case, the round-the-clock camera has been a vital tool for accountability as Mr. Nichols’s death has unleashed pain and anger in Memphis and around the country.
“It just so happens that in the case of Tyre, those cameras worked out in that way,” said Chelsea Glass, an organizer with Decarcerate Memphis, a group pushing for overhauling the criminal justice system.
The bulk of the footage released by city officials on Friday came from body cameras and showed Mr. Nichols, who the police initially said had been stopped for reckless driving, being pulled from his car and then running away.
More on the Death of Tyre Nichols
But the release also included about 31 minutes of video taken by the SkyCop, starting with a feed showing a tranquil winding street lined with brick homes before panning over to where officers had stopped Mr. Nichols on foot.
From then on, it captured a scene of escalating brutality as well as the immediate aftermath: The footage showed the officers kicking Mr. Nichols and pummeling him with a baton. Minutes later, he could be seen slumped on the ground against a police car, without receiving any care from officers or medics who had arrived at the scene.
“That particular video is what, I think, demonstrated not just the inhumanity but the grave disregard for this man’s rights and his life,” said the Rev. Dr. J. Lawrence Turner, the pastor of the Mississippi Boulevard Christian Church in Memphis, where Mr. Nichols’s funeral is to be held on Wednesday.
“The sky cam video makes the difference,” Pastor Turner said, adding that if “we were only left with the body cam footage,” it would still be harrowing and infuriating, but possibly not as conclusive to prosecutors as they considered charges against the officers. Five of them were charged with second-degree murder, among other things, last week for the death of Mr. Nichols.
The SkyCop camera that captured the beating is one of more than 2,000 that have been stationed around the city, all of which send back live feeds to the Police Department’s real-time crime center. Operators there are able to pan and zoom the cameras like the one providing footage in this case, which have a range of about 200 feet.
“I actually placed that camera there,” said Joe Patty, a retired lieutenant who served as the Police Department’s video surveillance manager and now, as a security consultant, works for SkyCop, a Memphis-based company.
Many of the SkyCop cameras in Memphis were initially installed more than a decade ago, mostly in affluent neighborhoods, as community groups raised the money to buy them and donate them to the city. But in 2016, the city purchased 80 SkyCops and placed them largely in areas that are predominantly African American and impoverished, and that have had persistent struggles with crime.
Even if many in the community expressed gratitude for the SkyCop footage of Mr. Nichols’s beating, it did not erase the skepticism that many still have about the cameras — or more to the point, the police force that operates them.
“It’s not really about the cameras,” said Duane T. Loynes Sr., a professor at Rhodes College in Memphis whose research focuses on the strained relationship between the Black community and law enforcement. “It’s about who’s in charge of the cameras.”
Law enforcement agencies around the country have deployed sprawling networks of cameras, with advocates describing them as a powerful tool for combating street crime and guarding against terrorism. Many of those systems now employ more advanced technology, including artificial intelligence and facial recognition. Studies have shown that facial recognition software can return more false matches for African Americans than for white people, a concern that has been raised in Detroit.
In Memphis, Mr. Patty said the SkyCop cameras do not use facial recognition technology, but some of the devices are outfitted with license plate readers and they do have motion sensors that alert the operators to movement.
Mr. Patty said the SkyCops, with their bright blue lights, were designed to be a conspicuous presence in the hope of discouraging criminal activity.
“The unknown factor is what you deterred,” he said. “There’s no way to figure that into an equation.”
Still, Mr. Patty said they were seen as a source of comfort in some neighborhoods, particularly where residents had raised money to install them. “I never had a complaint of someone wanting to take a camera down,” he said. “It was always, ‘Please can we have more.’”
But detractors have pointed out that violent crime increased in Memphis even after SkyCops were installed across the city. Larry Turnage, 64, who lives near the site of Mr. Nichols’s beating, said he did not think they helped. “They’re going to commit crime regardless,” he said. “It doesn’t matter.”
Chad A. Marlow, a senior policy counsel for the American Civil Liberties Union who focuses on privacy and surveillance issues, said that studies have shown that mounted camera systems do not deter crime. If anything, he added, the footage of the Memphis officers helped bolster those findings. “The police officers knew the camera was there and obviously it did not deter their bad behavior,” Mr. Marlow said.
“It does from time to time capture evidence of wrongdoing and that is certainly what occurred here,” he added. “But ultimately what you have is a tool that brings more police into these communities and creates more dangerous police interactions, and in this one case, it happens to provide evidence of police misconduct.”
Professor Loynes said the footage showed something that was no surprise to many in Memphis, where nearly two-thirds of residents are Black. “For Black Memphians, they didn’t need to see it, they’ve lived it,” he said.
He said that camera footage alone was not always enough to bring criminal charges against officers or lead to firings and promises of making changes to policing policy. There have been cases, he noted, where video footage had clearly shown police aggression but they had not resulted in criminal charges, like that involving Eric Garner, the 43-year-old Black man from Staten Island who died in 2014 after a New York police officer placed him in a chokehold.
“There’s a completely valid alternative universe where we have those videos,” he said, “and those officers are still not held accountable.”
In this version of events, though, many in the community were praising the charges and the role the SkyCop camera had played. “I’m glad that camera was here,” said Praylen Dickerson, who lives in the neighborhood.
Marcus Belton also stopped by the scene of Mr. Nichols’s beating to pay respects to Mr. Nichols. “It’s a proven fact that it worked then,” Mr. Belton said of the camera above, referring to the night of Jan. 7. “It worked magnificently.”
On Sunday, Mr. Dickerson, 63, brought a single rose to lay at the corner of Castlegate and Bear Creek Lanes, where a memorial for Mr. Nicols has grown in recent days.
He looked up at the camera above the intersection and the white box stamped in blue with the letters “MPD” and the Police Department’s insignia.
“They’re probably watching us right now,” Mr. Dickerson said.