When Wesley Lowery was covering the protests sparked by the fatal shooting of Michael Brown in 2014, his editors were always asking questions.

From his vantage point in Ferguson, Missouri, The Washington Post reporter saw frustration from protesters who insisted Brown's death at the hands of a police officer was not an isolated incident. Police unions insisted these killings were rare. So, editors wanted to know: Who was right?

"But, to our surprise, there was no accurate national data on these killings by police," Lowery told Poynter in an email. "...Several editors, researchers and reporters at The Post began to ask ourselves: If no one else is keeping this data, could we compile it?"

Thus began an ambitious effort from The Washington Post to tally every single individual shot to death by police in the United States throughout the year. Using news reports, public records, Internet databases and original reporting, Lowery and his colleagues determined that fatal police shootings were anything but rare: Nearly 1,000 people were killed by police in 2015. Moreover, their digging revealed that unarmed Black men are seven times as likely as Whites to die by police gunfire.

Why did it take the media so long to realize the extent of the killings? As part of Poynter's ongoing series on social justice journalism leading up to the centennial edition of the Pulitzer Prizes, we asked Lowery how the media came around to covering police shootings as a systemic issue.

You chronicled the fatal police shooting of Michael Brown, an unarmed Black man, in 2014. Did your experience covering that incident inform the reporting for this project? If so, how?

By the time our database project launched in full, we as a newsroom had covered the deaths of Michael Brown, Tamir Rice, Eric Garner, Walter Scott and Freddie Gray. And those reporting experiences on the ground, often led by reporters including me, Kimberly Kindy and Keith Alexander, informed not only our reporting targets, but also our broader understanding of the stories we were trying to tell.

Since we were building the database from scratch, we had to decide what categories to track — much of which was determined by our previous analysis of these kinds of incidents. We knew that it was important to determine whether people were armed or not, for example.

According to your data, unarmed Black men are seven times as likely as unarmed Whites to die by police gunfire. In your reporting, did you come across any explanations for that statistic?

One thing we did well, I think, was attempt to lay out our findings in ways that were divorced from the emotional conversation happening nationally. We wanted our work and analysis to be unimpeachable, no matter a given reader’s biases as they relate to police or the ongoing protest movement.

The data on unarmed Black men was revelatory, in part because it buoyed one of the central claims of the ongoing protests: that Black men were disproportionately being killed by police officers.

Activists and others who study criminal justice often point to our finding as evidence of implicit racial bias in policing, or to underscore the theory that Black communities are over policed. Those more sympathetic to law enforcement tend to insist that this disparity is because of higher levels of crime in Black areas of cities — but our analysis has consistently found that the location of police shootings does not correlate with rates of violent crime.

During your reporting, did your team unearth any other statistics that surprised you? What conclusions do you draw from all the data you've gathered?

It was initially shocking to me how many of the shootings involved people who were either in the midst of a mental health crisis or who were explicitly suicidal — which ended up being the subject of one of our first major pieces off of the database. In total, a quarter of all of the fatal shootings by police officers in 2015 was of someone who was mentally ill. Despite this, many departments lack the kind of specialized training that is essential to deescalating an incident with someone in the midst of a mental health crisis.

Our data effort — which documented more than twice the number of fatal shootings than FBI had ever recorded — underscored the failure of the federal government and state governments to adequately measure and report how many people are being killed by the police each year. Without that data, police chiefs and police trainers are forced to rely on anecdote and emotion when making policy decisions about tactics and training that have life and death implications.

Another major finding of ours was that, while officers insist most of them never fire their weapons on the job, we found more than 50 officers involved in an on-duty shooting last year had previously been involved in a shooting.

Do you see your work as fitting into the broader pattern of American journalism that reveals injustices within our society? If so, what inequities did your work expose?

I see our work as an extension of a tradition of journalism that holds powerful institutions accountable and applies skepticism to institutions and centers of power. People often forget that police officers are an extension of the government. That when the police kill someone, it is the government killing someone.

So, if a single police officer kills a single person under circumstances in which they shouldn’t, that is a major story. And, in order to determine whether that has happened, the media must examine each police shooting or death in custody (which, again, was impossible before anyone was keeping count).

In a recent column for the Chicago Tribune, Christopher Benson notes that too often in media there is “an unquestioned belief in the rightness of our institutions.” After a police shooting, there are often calls by police officials and amplified by the media to “let the process play out.” But that is only a route to justice if the process in and of itself is just.

Our reporting during the last 18 months have found that police officers are almost never charged with crimes for on-duty shootings and when they are almost never convicted. That is true even of shootings in which the officer involved has violated department policy or best practices.

We’ve found that body cameras — held out by many as a silver bullet — are creating new transparency issues — with videos more often than not shielded from the public view.

During the latter half of 2014 and into 2015, the issue of police killing unarmed Black men was thrust into the public consciousness in a way that it hadn't been before. Is that a result of better media coverage? The rise of social media? A profusion of body cameras? Something else?

It was a result of social media and of a flattening of the media landscape. I think an honest assessment of most of the media coverage, especially in the immediate, of any of the incidents at the end of 2014 would find it deeply lacking — in context, in skepticism and in ability to see the structural and systemic stories behind the daily headlines. The man or woman on the street protesting is almost never truly there because of the police shooting that happened earlier that day. They are much more often there because that day’s shooting was what they considered the last straw.

Were it up to traditional media, we likely never would have known the stories of Michael Brown, or Eric Garner, or Tamir Rice, or Sandra Bland.

Rather, these stories spread and bled into the national consciousness because of the power of the people who witnessed these incidents to show what they had seen through cell phone cameras, and the power of other citizens, enraged by what they saw, to spread the word.

While reporting on the shooting of Michael Brown in Ferguson, you and The Huffington Post's Ryan Reilly were arrested by St. Louis County police in a town where Black people face disproportionately high levels of excessive force from law enforcement. Do you think that interaction is indicative of any trends in American policing writ large?

Too often those in power, whether they be politicians or patrol officers, do not respect the role of the press, rather they resent it and take active steps to demonize, control, or silence the media. Whether it be through illegally detaining reporters doing their job, or refusing to release records that provide crucial context to understand how they do their jobs, too often police agencies are on the wrong side of transparency.

Hopefully, through the reporting our team has done, more police departments are beginning to see the value that comes with accountability and transparency.

During the Civil Rights movement, most of the journalism that received public adulation was undertaken by White reporters and editors, even though Black journalists at Black publications were doing a better job of covering the ongoing tumult.

Fast-forward more than half a century, and we have prominent Black journalists at mainstream outlets — The Washington Post, MSNBC and The New York Times — telling the story. Does this shift result in a different kind of coverage from America's publications of record? Is it important that the people telling these stories have firsthand experience with the systematic injustice they're chronicling?

It’s extremely important that outlets reflect the complexity and the diversity of the nation they are charged with covering. And, equally important to diversity among the ranks of reporters who are covering a given story or series of stories is the diversity of the editors and other decision makers who are crafting headlines, story structure, and making decisions about allocation of resources.

It’s impossible to accurately tell a story or fairly portray a reality that you do not understand, and so I think it is no coincidence that a lot of the best reporting coming from the ground, whether it be in Ferguson, or Baltimore, or elsewhere has come from people like Yamiche Alcindor and Trymaine Lee.