IF Black Lives Matter had a cold-case division or a team of street lawyers committed to investigating the unresolved killings of the past, then the case of 16-year-old Larry Payne from Memphis would be at the top of their pile. One impediment stands in their way – there were no cameras.

In March 1968, Payne was heading home with a group of friends to his mother’s apartment in Fowler Homes, a maze of low-rise houses in central Memphis. The boys were being pursued by officers on foot who suspected them of being in possession of a television set looted from a Sears Roebuck store.

The teenagers scattered. Patrolman LD Jones and his partner followed Payne into the cluttered semi-darkness of a basement area. They claimed that the teenager then turned on them brandishing a knife and that they were forced to shoot him in self-defence.

Residents had flocked out from their apartments to watch the commotion. None of them saw a television nor a knife, but they heard a muffled blast from a 12-gauge shotgun. One resident told a contradictory story. ‘‘Larry had his hands up and his back to the door of the storage room. His hands were behind his head when the police shot him.’’ Another witness said: ‘‘The shorter policeman shot him. It was a muffled sound, like busting a sack. The gun was touching his stomach. Others claim they overheard the thinner of the officers say “you didn’t have to shoot him”.

History was not kind to Larry Payne. Enraged by his killing, Dr Martin Luther King telephoned Payne’s mother to comfort her and agreed that the next time he was in Memphis he would visit the family. It was a promise he never kept; the next time he was in Memphis, Dr King was assassinated at the Lorraine Motel and, like a giant oak tree, his death overshadowed everything else in a racially divided city. Larry Payne’s death shrivelled from view. None the police officers was ever charged, and a few years later, in a deeply suspect clean-up operation, all the case evidence, including the police gun that killed Larry Payne, was thrown into the Mississippi River, never to be retrieved.

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With some right on their side, Black Lives Matter would point to the Larry Payne killing in 1968 and say nothing much has changed, but that would only be true of the death itself. Much has changed, not least the media scrutiny of police killings and the camera technology that has taken centre stage in the recent disturbances across America.

The summer of rebellions has been played out like a global drama on video – the statue of the Bristol slave owner

Edward Colston being dragged off its plinth and then rolled into the docks; the final minutes of George Floyd’s life in Minneapolis, and the massed ranks of demonstrators in their Covid-19 protest masks. They are the memorable images – burnt into our minds – from thousands of hours of footage from around the world.

This month The New York Times has launched a landmark journalistic project. A team has been set up to analyse more than 60 videos shot during the first 10 days of demonstrations after the death of George Floyd.

It’s easy to overlook how pervasive camera technology has become. Smart-phone footage dominates the haul that The New York Times has amassed, but there are also helmet-cams from cyclists, CCTV footage from surrounding stores and images captured by journalists working freelance or for other titles.

It will be a painstaking job making sense of all the images and then converting them into specific stories: who are the people involved, who are the police officers, why did they react so aggressively and what triggered the moment captured by the video sources? The images alone will not suffice.

As the NYT journalists set about their task the raw footage raises the bar on the term video journalism. In the early days of digital delivery the assumption was that a video journalist would record

activities on a lightweight camera to deliver stories to a newspaper and its nascent website. Now the term is being turned on its head; a video journalist might as reasonably be someone who analyses video footage, scraped from the web, to unearth a story buried in the white noise of events.

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The dig goes deeper. A coalition of media organisations, including The New York Times, petitioned the courts to obtain footage from the police body-cameras which surround the death of George Floyd. The footage was made available for viewing by appointment at the Hennepin County Government Centre in downtown Minneapolis — in a conference room with a dozen laptop stations.

Significantly, the footage was not allowed to be copied, recorded nor were there facilities to pause images, replay events or zoom in on certain moments. The police should be congratulated for their baby-step transparency but excoriated for their refusal to allow journalists scrutiny of the footage. Their rules of engagement suggest – possibly wrongly – that they have something to hide.

Transcripts were released of the body-camera footage from two of the four police officers charged in the killing of Floyd. Ironically, they were released last week as part of a motion on behalf of one of the junior officers, Thomas Lane, who is hoping to have the case against him dismissed.

He was not primarily involved in the violence that led to the death of George Floyd but the transcript did reveal that Floyd was given no explanation for why he was being questioned before Lane pointed a gun and swore at him, forcing him out of his vehicle into the street.

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The video offers the fullest portrait yet of the tragic events around Floyd’s killing. It begins with officers driving to the scene after a convenience store clerk called 911 and said a man had used a counterfeit $20 bill, and it ends showing officers on the street discussing what happened, after Floyd is driven away in an ambulance.

At one point, in footage not previously seen, the officers are shown dragging Floyd to the ground after he resisted being put in the squad car. The footage shows Floyd repeatedly telling officers he is claustrophobic and it is clear he posed no physical threat to the officers.

Even after he was handcuffed and searched for weapons, the officers seemed to be more concerned with supressing his body than saving his life. Floyd is shown with his head down, crying, as if he were in the throes of a panic attack.

The prevalence of video imagery and the new journalistic scrutiny of cell-phone imagery has not gone unnoticed and has provoked a backlash from serving police officers and their most senior management. The New York Police Department (NYPD) is pressing ahead with new rules to tighten the permission around journalism. In a press release published on Wednesday, the NYPD outlined a wide range of offences that can cost reporters their credentials, including being arrested, being perceived not to be complying with police orders or engaging in conduct that “interferes with legitimate law enforcement needs”.

Off the record, the NYPD claim that social media has led to an increase in so-called citizen journalists, who arrive as part of the demonstration and are partisan in their attitudes to the police.

In what has become a philosophical argument about the ethics of journalism they claim that some journalists lack objectivity or sufficient ‘‘distance’’ from events and that their conduct, such as participating in chanting, makes them untrustworthy.

Others turn up with no press or media credentials. Set against that is the vantage point of embedded journalism, those that believe that to be close to the activity gives the journalist a unique insight into events. That may bring the journalists behind the police lines but equally they will be among demonstrators.

Video footage is the raw material of great stories yet to come, but it raises the bar on journalistic ethics and the already compromised policies of policing demonstrations. One thing is certain, with the capacity to publish instantly on the worldwide web, the idea that evidence can be destroyed by being thrown in a river is a thing of the past.