While an increasing number of police departments have the cameras, the rules governing their use can be unclear.
Protesters massed on Charlotte’s streets for a third night as pressure mounted on authorities to release a video that could resolve different accounts of the latest police killing of a black man in the United States.
Demonstrators on Thursday chanted “Release the tape” and “We want the tape” while briefly blocking an intersection near the Bank of America headquarters and later climbing the steps in front of the city government centre to vent their anger over the shooting dead of 43-year-old Keith Lamont Scott.
Later, several dozen demonstrators gathered on a highway, but they were pushed back by police in riot gear.
The protests were calmer than on previous nights. A midnight-to-6am curfew imposed by the mayor aimed to add a stopping point for the demonstrations but many marched on past 12am, with police saying they would not enforce the curfew as long as the demonstrations remained peaceful.
One protester Al Jazeera spoke to, when asked why they were marching after midnight, simply said: “Because black lives matter”.
On Wednesday, a night in which at least 44 people were arrested, one protester who was shot was taken to hospital.
That protester, 26-year-old Justin Carr, has now died of his wounds, officials said. City officials said police did not shoot the man and no arrests have been made over his death, but protesters say police fired the shot that killed him. A murder investigation is under way.
A state of emergency was imposed after Carr was shot.
Al Jazeera’s Alan Fisher, reporting from Charlotte, said: “The street is packed with people who have decided that the curfew means nothing to them, and they are going to continue protest.”
So far, police have resisted releasing police dashcam and body camera footage of Scott’s death on Tuesday.
His family was shown the footage on Thursday and demanded that police release it to the public. The family’s lawyer said he couldn’t tell whether Scott was holding a gun, referring to a claim made by police and denied by witnesses.
Charlotte-Mecklenburg Police Chief Kerr Putney said earlier that the video would only be made public when he believed there was a “compelling reason” to do so.
“You shouldn’t expect it to be released,” Putney said. “I’m not going to jeopardise the investigation.”
Charlotte is the latest US city to be shaken by protests and recriminations over the death of a black man at the hands of police, a list that includes Baltimore, Milwaukee, Chicago, New York and Ferguson, Missouri.
In Tulsa, Oklahoma, on Thursday, prosecutors charged a white officer with manslaughter for killing an unarmed black man on a city street last week.
Charlotte police have said that Scott was shot dead on Tuesday by a black officer after he disregarded loud, repeated warnings to drop a gun. Neighbours, though, have said he was holding only a book, and that the officer who killed him was white. The police chief said a gun was found next to the dead man, and there was no book.
Putney said that he has seen the video and it does not contain “absolute, definitive evidence that would confirm that a person was pointing a gun.” But he added: “When taken in the totality of all the other evidence, it supports what we said.”
Justin Bamberg, a lawyer for Scott’s family, watched the video with the dead man’s relatives. He said Scott got out of his vehicle calmly.
“While police did give him several commands, he did not aggressively approach them or raise his hands at members of law enforcement at any time. It is impossible to discern from the videos what, if anything, Mr Scott is holding in his hands,” Bamberg said in a statement.
Scott was shot as he walked slowly backwards with his hands by his side, Bamberg said.
The lawyer said at a news conference earlier in the day that Scott’s wife witnessed his killing, “and that’s something she will never, ever forget.”
That is the first time anyone connected with the case has said Scott’s wife witnessed the shooting. Bamberg gave no further details on what she saw.
Experts who track shootings by police noted that the release of videos can often quell protest violence, and that the footage sometimes shows that events unfolded differently than the official account.
“What we’ve seen in too many situations now is that the videos tell the truth and the police who were involved in the shooting tell lies,” said Randolph McLaughlin, a professor at Pace University School of Law. He said it is “irresponsible” of police not to release the video immediately.
According to a tally being kept by The Guardian media organisation, police have killed at least 194 black Americans so far this year. In all of 2015, police killed at least 306 black men.
The figures from 2016 suggest that while black Americans make up around 13 percent of the population, they make up about 25 percent of those killed by police.