The former Milwaukee police officer who shot and killed Sylville Smith, a 23-year-old black man, has been acquitted of first-degree reckless homicide charges on Wednesday.

Police said Dominique Heaggan-Brown, who is also black, shot and killed Smith after Smith took off during a traffic stop. Officials said Smith was armed with an allegedly stolen handgun, but Smith reportedly tossed the gun away, according to court documents, before Heaggan-Brown fired the fatal shot. (Investigators have declined to release body camera footage of the shooting until after they complete their investigation.)

The initial reports of the shooting led to hundreds of protesters gathering in parts of the city. The protests escalated into violence and riots the weekend following the shooting, leading to the destruction of several businesses and vehicles, including police cars.

Even before we knew much about the police shooting, including Smith’s identity and race, it was protested by Black Lives Matter activists as just another example of the racial inequities in the criminal justice system — an issue that rose to the national spotlight after the police shooting of Michael Brown in Ferguson, Missouri, in August 2014. The anger behind these disparities, along with longstanding racial tensions in Milwaukee, apparently fueled the riots.

Police shooting of Sylville Smith: what we know

At the time the violence broke through in August last year, we didn’t know much about the shooting. Soon after, the Milwaukee Journal Sentinel learned Smith's name and background from police sources and family.

Police stopped what they described as a suspicious rental car with two suspects, including Smith, in the afternoon of August 13. Smith, who allegedly had a stolen handgun, took off running.

According to court documents filed by the prosecution against Heaggan-Brown, at some point Smith turned to the officers and raised his gun. Heaggan-Brown fired one shot, which hit Smith in the arm. Smith then tossed the gun over a fence. But Heaggan-Brown fired another shot while Smith was unarmed, striking Smith in the chest and killing him. The two shots were fired within two seconds of each other.

The officer who shot and killed Smith had a body camera on him. The video was used as evidence in an investigation carried out by the Wisconsin Department of Justice. The jury did see the footage, but it has not yet been released to the public. According to TMJ, Milwaukee's NBC affiliate, it may be released now that the trial is over.

Last year, Wisconsin Attorney General Brad Schimel said releasing the video beforehand "would compromise the integrity of the investigation. It is sometimes necessary to confront witnesses with information they didn't know or they didn't know we know. I cannot have witness statements colored or tainted by what they are seeing from other sources."

Heaggan-Brown had six years of service with the Milwaukee Police Department. He had already been fired from MPD in October 2016 when he was charged with sexual assault in separate cases, the Associated Press reported:

According to a criminal complaint, Heaggan-Brown and another man went to a bar late on the night of 14 August where they drank heavily and watched television coverage of the riots. The man told investigators that Heaggan-Brown bragged that he could do anything he wanted without repercussions, and that he woke up to Heaggan-Brown sexually assaulting him. Heaggan-Brown also was charged with soliciting two other people for sex several times since December 2015 and with sexually assaulting another unconscious person in July 2016 and photographing that victim naked. He faces two felony counts of second-degree sexual assault, two misdemeanor prostitution counts and one felony count of capturing an intimate representation of a person without consent.

Smith's mother, Mildred Haynes, told the Journal Sentinel that her son obtained a concealed carry license because he had previously been shot twice and robbed four times. She said she could not envision him brandishing a weapon at the police, but could see him trying to run and hide.

Police said Smith had a "lengthy arrest record." The Journal Sentinel also reported that Smith was charged in 2015 in a shooting and then charged again for trying to intimidate a witness in that same shooting — but both charges were dismissed. Despite his arrest history, Smith does not seem to have had a felony record; he had one misdemeanor conviction for carrying a concealed weapon.

But Smith’s previous convictions aren't what's relevant to the shooting; it's whether he was holding and trying to use his gun on the officers at the time he was shot. The legal standard for use of force requires officers to reasonably perceive a threat at the moment of use of force.

This verdict follows another that came down Tuesday evening, regarding the shooting of Minnesota resident Philando Castile by Officer Jeronimo Yanez, who was cleared of all charges. Both cases involved video footage of these shootings, which have, in the end, done little to lead to any criminal punishment for the officers involved in shooting these men. In many cases, several police accounts of shootings or killings have fallen apart with video evidence, making it especially hard for activists to take cops at their word — but seemingly not as difficult for juries to clear those officers.

Milwaukee's riots and protests began in response to the shooting — and much more

As news of the shooting broke out, at least 200 people gathered — apparently organizing through social media — in demonstrations. Those protests then quickly escalated, breaking into riots.

According to the Milwaukee Journal Sentinel and ABC News, people set fire to six businesses. They fired off gunshots. They smashed and burned police cars. They threw objects, including bricks, at police. And they at one point turned on reporters: "One reporter was shoved to the ground and punched," the Journal Sentinel reported.

Milwaukee Police Chief Ed Flynn said 17 people were arrested during the first night of protests, all of whom had criminal records.

"This is a warning cry. Where do we go from here? Where do we go as a community from here?"

In light of the violence, the mayor pleaded with people to go home. "If you love your son, if you love your daughter, text them, call them, pull them by the ears and get them home," Milwaukee Mayor Tom Barrett said. "Get them home right now before more damage is done."

But protests continued until the night of August 14. Although there was no widespread property damage like on the night of August 13, there were reports of objects — rocks and bricks — thrown at police and gunshots, which apparently forced police to use an armored vehicle to evacuate an injured man.

The tensions continued even after Wisconsin Gov. Scott Walker activated the National Guard to help keep the peace after the first night of protests.

City Alderman Khalif Rainey said the area of the riots and demonstrations had become a "powder keg" this summer:

This entire community has sat back and witnessed how Milwaukee, Wisconsin, has become the worst place to live for African Americans in the entire country. Now this is a warning cry. Where do we go from here? Where do we go as a community from here? Do we continue — continue with the inequities, the injustice, the unemployment, the under-education, that creates these byproducts that we see this evening? … The black people of Milwaukee are tired. They’re tired of living under this oppression. This is their existence. This is their life. This is the life of their children. Now what has happened tonight may have not been right; I’m not justifying that. But no one can deny the fact that there’s problems, racial problems, here in Milwaukee, Wisconsin, that have to be closely, not examined, but rectified. Rectify this immediately. Because if you don’t, this vision of downtown, all of that, you’re one day away. You’re one day away.

Historians say these types of violent outbursts are typically rooted in longstanding anger toward a system that has in many ways failed them. "People participate in this type of event for a real reason," Darnell Hunt, a UCLA professor who's studied the 1992 Rodney King riots in Los Angeles, told me during the Baltimore riots after Freddie Gray died in police custody. "It's not just people taking advantage. It's not just anger and frustration at the immediate or proximate cause. It's always some underlying issues."

For example, a previous analysis found that the Milwaukee metropolitan area is the most racially segregated in the country. It is possible the issues connected this segregation — more areas of concentrated poverty, bad schools, and high crime — have long angered residents. Compounded with the racial disparities in the criminal justice system, people were clearly furious — and lashed out.

Black people are much more likely to be killed by police than their white peers

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 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.

In the 1980s, a pair of Supreme Court decisions — Tennessee v. Garner and 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.

So like Yanez earlier this week, Heaggan-Brown counts toward the trend: that it's truly rare for an officer who shot and killed a man, in this case, Smith, to be convicted of a crime.

Watch: Why it's so important to film the police