When a video clip of Los Angeles police officers shooting a homeless man on Skid Row went up on Facebook on Sunday, it immediately went viral—an overused, cliched term at this point, but it's the best description of the way a random bystander's cellphone footage could spread to hundreds of thousands of people in just a few hours.

The video is very difficult to watch, for all the reasons you'd expect. There's a brief scuffle; someone shouts, "Drop the gun!" Then there are several shots fired at the man as he lies on the ground, with a scrum of officers around him. You can hear the crowd around—they're understandably shocked. One voice, perhaps the man recording, keeps intoning, "motherfucker, motherfucker." Soon the bystanders start screaming at the police, furious and upset about what just happened.

Police say they'd already used a stun gun and it had failed to subdue the man—known as "Africa," not identified by name—and that he then reached for an officer's gun. While it's tough to tell what's going on in the cellphone footage, the Los Angeles Times reported that in an enhanced version of the film, the man clearly reaches for the gun but it's impossible to tell whether he touches it. Two officers and a sergeant fired shots at the man, police said, and he was pronounced dead at the scene. Police had been called because of an altercation involving a tent.

In the Michael Brown shooting, Officer Darren Wilson also alleged that Brown lunged for his gun, an idea that was hotly disputed. But there was no way to prove what happened either way. What makes the Los Angeles shooting different is how extensively recorded it was. There's the original video that was posted to Facebook (and has since been removed). There are at least two surveillance cameras on the site. And at least one of the officers involved in the incident was wearing a body camera.

That has to make it one of the more carefully recorded instances of the many episodes of police-related violence that have roiled the country, from Staten Island to Cleveland to Ferguson. Video of Eric Garner's death is one reason it became such a cause—anyone could watch the police choking him, see him gasping for breath. In Cleveland, film showed how quickly an officer opted to fire at Tamir Rice, undercutting the official department narrative.

Part of the logic behind body cameras is that they will capture these moments. But to what end? As a deterrent, as a tool of justice, or as both? Perhaps this case will offer some indication of how effective the cameras can be. Many people are already asking what the point of the cameras is if they didn't stop what they see as excessive force in the L.A. case. The results of studies on body-cam use around the world don't offer much hope that they will produce huge changes.

If the point of the cameras is deterrence, it will take some instances of police misconduct being caught on tape and punished before officers' behavior changes. If, however, the point is simply to make sure there's a full record of cases in which citizens are shot so that justice can be done, it's harder to tell what role the cameras will serve here, not least because the man was reportedly reaching for a gun, and the body-cam video has not been made public.

Unlike, for example, a dashcam video of a South Carolina state trooper shooting an unarmed man, the underlying facts here may be impossible to adjudicate objectively, even with so much documentary evidence. Some people will see the police response to a minor threat escalating outrageously; others will see officers who had reason to worry for their lives.

If the abundance of video makes this killing different, the case remains depressingly familiar in other ways. Watching police argue with a man who acquaintances described as mentally ill, it's impossible not to wonder what could have been done differently to avoid getting to the point where the man was on the ground and reaching for a pistol. How many other approaches might have worked?

Certainly, the bystanders were upset. On the video, voices accuse the police of cowardice and complain that there were more than enough officers to ensure a peaceful resolution. "That man never was a threat. The amount of officers present at the time could have subdued him," one man told the Times. Even if the courts decide that the police were within reason to fire on the man, the court of public opinion may pass a different verdict on the Los Angeles Police Department, which is no stranger to accusations of excessive force.

Race is, once again, an ingredient in this incident, though it's not as simple as white police and a black victim. On the video taken by a witness, many in the crowd say that one of the officers who shot the man was black, and some accost that officer in racial terms. (There's something unsettling about seeing a video of a black man being killed passed around so blithely.)

The killing comes just as the Justice Department is reportedly preparing to release a report finding extensive racial bias in policing in Ferguson. The department has apparently decided not to charge Wilson with civil-rights abuses, but outgoing Attorney General Eric Holder says he wants to lower the bar for civil-rights cases.

Just last month, FBI Director James Comey addressed accusations of racism in law enforcement, pleading that most police officers are not racially biased. But as this incident demonstrates, the question is not the intentions of the officers involved or their race. The question is about police policy and procedures, and whether they produce disparate results for blacks and whites. All indications are that they do.

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