Here’s what we know about yet another police shooting to make national headlines.

Updated by German Lopez  @germanrlopez  german.lopez@vox.com Sep 21, 2016, 1:45p

Terence Crutcher, a black 40-year-old man, was unarmed. He appeared to be cooperating with police, with his hands up as they escorted him toward his car. Yet suddenly, in moments that were largely obstructed in the videos released by the Tulsa Police Department on Monday, an officer shot and killed Crutcher.

According to the local newspaper Tulsa World, police were responding to an unrelated call on Friday, September 16, when they spotted Crutcher’s stalled car. We don’t know what happened when police arrived at the scene. Instead, the videos begin as Crutcher is guided by officers, one of whom is aiming her gun at him, slowly to his car. He has his hands up during this time.

Police say that Crutcher then failed to follow orders — leading officer Betty Shelby to fire her weapon and officer Tyler Turnbough to use his Taser on Crutcher. By the looks of the videos, the Taser and gun were seemingly fired almost simultaneously.

RelatedWhy police so often see unarmed black men as threats

The videos — one a police dashboard camera on the ground, another on a helicopter in the air — are obstructed by officers and Crutcher’s car at the exact moment he was shot. That makes it hard to discern whether Crutcher had his hands up right as Shelby pulled the trigger.

But Crutcher had his hands up in the air until at least the seconds before he was shot, and he appears — although, again, it’s hard to say for sure — to put his hands on the roof of his car right before the officer fired.

Police found no gun on Crutcher or in his car.

Law enforcement reportedly found PCP in Crutcher's car. An attorney for Shelby told Tulsa World that she thought Crutcher was on drugs when she shot him. But that has no bearing on whether the shooting was legally justified — unless Crutcher acted in a dangerous or threatening manner before he was shot, which the video doesn't show.

A local investigation into the shooting is currently underway. The US Department of Justice also opened an independent investigation into the shooting.

The shooting has already inspired strong condemnations from the Black Lives Matter movement, with activist and New York Daily News columnist Shaun Kingcalling for the police officers involved to be arrested. The shooting exemplifies yet another example of the racial disparities in police use of force — showing that even when a black man holds his hands up, he can still be at risk of getting shot and killed by the police.

An analysis of the available FBI data by Vox’s Dara Lind shows that US police kill black people at disproportionate rates: They accounted for 31 percent of police killing victims in 2012, even though they made up just 13 percent of the US population. Although the data is incomplete, since it’s based on voluntary reports from police agencies around the country, it highlights the vast disparities in how police use force.

Black teens were 21 times as likely as white teens to be shot and killed by police between 2010 and 2012, according to a ProPublica analysis of the FBI data. ProPublica’s Ryan Gabrielson, Ryann Grochowski Jones, and Eric Sagara reported: "One way of appreciating that stark disparity, ProPublica’s analysis shows, is to calculate how many more whites over those three years would have had to have been killed for them to have been at equal risk. The number is jarring — 185, more than one per week."

There have been several high-profile police killings since 2014 involving black suspects. In Baltimore, six police officers were indicted for the death of Freddie Gray while in police custody. In North Charleston, South Carolina, Michael Slager was charged with murder and fired from the police department after shooting Walter Scott, who was fleeing and unarmed at the time. In Ferguson, Darren Wilson killed unarmed 18-year-old Michael Brown. In New York City, NYPD officer Daniel Pantaleo killed Eric Garner by putting the unarmed 43-year-old black man in a chokehold.

BLACK TEENS WERE 21 TIMES AS LIKELY AS WHITE TEENS TO BE SHOT AND KILLED BY POLICE BETWEEN 2010 AND 2012

One possible explanation for the racial disparities: Police tend to patrol high-crime neighborhoods, which are disproportionately black. That means they're going to be generally more likely to initiate a policing action, from traffic stops to more serious arrests, against a black person who lives in these areas. And all of these policing actions carry a chance, however small, to escalate into a violent confrontation.

That's not to say that higher crime rates in black communities explain the entire racial disparity in police shootings. A 2015 study by researcher Cody Ross found, "There is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates." That suggests something else — such as, potentially, racial bias — is going on.

One reason to believe racial bias is a factor: Studies show that officers are quicker to shoot black suspects in video game simulations. Josh Correll, a University of Colorado Boulder psychology professor who conducted the research, said it’s possible the bias could lead to even more skewed outcomes in the field. "In the very situation in which [officers] most need their training," he said, "we have some reason to believe that their training will be most likely to fail them."

Part of the solution to potential bias is better training that helps cops acknowledge and deal with their potential subconscious prejudices. But critics also argue that more accountability could help deter future brutality or excessive use of force, since it would make it clear that there are consequences to the misuse and abuse of police powers. Yet right now, lax legal standards make it difficult to legally punish individual police officers for use of force, even when it might be excessive.

Police only have to reasonably perceive a threat to justify shooting

Legally, what most matters in police shootings is whether police officers reasonably believed that their lives were in immediate danger, not whether the shooting victim actually posed a threat. So in the Crutcher case, the question is whether the officers involved thought he reasonably posed an immediate threat to them or others — and what exactly Crutcher did to warrant that.

In the 1980s, a pair of Supreme Court decisions — Tennessee v. Garnerand Graham v. Connor — set up a framework for determining when deadly force by cops is reasonable.

Constitutionally, "police officers are allowed to shoot under two circumstances," David Klinger, a University of Missouri St. Louis professor who studies use of force, told Vox’s Lind. The first circumstance is "to protect their life or the life of another innocent party" — what departments call the "defense-of-life" standard. The second circumstance is to prevent a suspect from escaping, but only if the officer has probable cause to think the suspect poses a dangerous threat to others.

The logic behind the second circumstance, Klinger said, comes from a Supreme Court decision called Tennessee v. Garner. That case involved a pair of police officers who shot a 15-year-old boy as he fled from a burglary. (He’d stolen $10 and a purse from a house.) The court ruled that cops couldn’t shoot every felon who tried to escape. But, as Klinger said, "they basically say that the job of a cop is to protect people from violence, and if you’ve got a violent person who’s fleeing, you can shoot them to stop their flight."

THE KEY TO BOTH OF THE LEGAL STANDARDS IS THAT IT DOESN’T MATTER WHETHER THERE IS AN ACTUAL THREAT WHEN FORCE IS USED

The key to both of the legal standards — defense of life and fleeing a violent felony — is that it doesn’t matter whether there is an actual threat when force is used. Instead, what matters is the officer’s "objectively reasonable" belief that there is a threat.

That standard comes from the other Supreme Court case that guides use-of-force decisions: Graham v. Connor. This was a civil lawsuit brought by a man who’d survived his encounter with police officers, but who’d been treated roughly, had his face shoved into the hood of a car, and broken his foot — all while he was suffering a diabetic attack.

The court didn’t rule on whether the officers’ treatment of him had been justified, but it did say that the officers couldn’t justify their conduct just based on whether their intentions were good. They had to demonstrate that their actions were "objectively reasonable," given the circumstances and compared to what other police officers might do.

What’s "objectively reasonable" changes as the circumstances change. "One can’t just say, 'Because I could use deadly force 10 seconds ago, that means I can use deadly force again now," Walter Katz, a California attorney who specializes in oversight of law enforcement agencies, said.

In general, officers are given lot of legal latitude to use force without fear of punishment. The intention behind these legal standards is to give police officers leeway to make split-second decisions to protect themselves and bystanders. And although critics argue that these legal standards give law enforcement a license to kill innocent or unarmed people, police officers say they are essential to their safety.

For some critics, the question isn’t what’s legally justified but rather what’s preventable. "We have to get beyond what is legal and start focusing on what is preventable. Most are preventable," Ronald Davis, a former police chief who heads the Justice Department’s Office of Community Oriented Policing Services, told the Washington Post. Police "need to stop chasing down suspects, hopping fences, and landing on top of someone with a gun," he added. "When they do that, they have no choice but to shoot."

Police rarely get prosecuted for shootings

Police are very rarely prosecuted for shootings — and not just because the law allows them wide latitude to use force on the job. Sometimes the investigations fall onto the same police department the officer is from, which creates major conflicts of interest. Other times the only available evidence comes from eyewitnesses, who may not be as trustworthy in the public eye as a police officer.

"There is a tendency to believe an officer over a civilian, in terms of credibility," David Rudovsky, a civil rights lawyer who co-wrote Prosecuting Misconduct: Law and Litigation, told Amanda Taub for Vox. "And when an officer is on trial, reasonable doubt has a lot of bite. A prosecutor needs a very strong case before a jury will say that somebody who we generally trust to protect us has so seriously crossed the line as to be subject to a conviction."

If police are charged, they’re very rarely convicted. The National Police Misconduct Reporting Project analyzed 3,238 criminal cases against police officers from April 2009 through December 2010. They found that only 33 percent were convicted, and only 36 percent of officers who were convicted ended up serving prison sentences. Both of those are about half the rate at which members of the public are convicted or incarcerated.

The statistics suggest that it would be a truly rare situation if the officer who shot and killed Crutcher was convicted of a crime. But video could potentially make a difference — as it did for prosecutors who pressed charges over the police shootings of Samuel DuBose in Cincinnati, Walter Scott in North Charleston, South Carolina, and Laquan McDonald in Chicago.