The internet Wednesday was abuzz with reactions to distressing footage of a mentally ill man dying at the hands of police officers in Dallas three years ago.

Tony Timpa, 32, who had called 911 for help, was pinned to the ground in a position that poses an elevated risk of suffocation. The officers who restrained him ignored his cries of distress and joked about waking him up in time for school after he had passed out.

Outrage over needless death due to excessive force by the police has become a sadly regular part of the news cycle in America. But this story differs from the typical scenario for highly publicized cases of deadly police violence in one notable way: The victim is white.

The conversation on police violence in the past five years, dominated by the Black Lives Matter movement, has focused almost entirely on race and racism, with such notable cases as the 2014 killing of Eric Garner, the African American man who was detained for selling loose cigarettes on Staten Island and who died after being put in a chokehold. That black Americans are in mortal danger from racist cops has become progressive dogma; a white person who calls the police on a black person for a trivial reason, activists say, puts that person’s life in danger.

And yet data, including a just-released study in the Proceedings of the National Academy of Sciences by Michigan State University psychologist Joseph Cesario, University of Maryland psychologist David Johnson and their colleagues, paint a more complicated picture.

According to the study, which examined a national database of fatal police shootings, there is no evidence that white police officers are more likely than black or Hispanic officers to kill black or Hispanic suspects. In other words, increasing racial diversity on the police force is unlikely to reduce fatal police shootings of racial minorities. Critics say the findings do not disprove the claim that racism plays a significant role in police shootings, since black and Hispanic cops are not immune to racial stereotyping. But the study also suggests that, overall, police shootings are not driven by racial bias. While racial disparities exist — in 2015, for example, African Americans made up 12 percent of the population of the United States but 26 percent of civilians fatally shot by police — they often mirror disparities in crime demographics.

Does this mean that there is no racial bias in policing? No. Other research has found that while blacks detained by the police were no more likely than white detainees to be shot, they were more likely to be hit, pushed to the ground and otherwise manhandled. And there is strong evidence that African Americans — especially men — are more likely to be stopped for the same behavior.

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Many black Americans feel singled out for demeaning and abusive treatment by police; while the causes of these tensions are complicated, this is an urgent problem. But it also is true that many Americans of all races — often, people with psychiatric ailments and substance-abuse problems like Timpa — die needlessly in police interventions when they have committed no crime and pose no danger.

We should do more to reduce the risk of such tragedies; but to deal with the problem, we need facts, not myths. Police attitudes are often part of the problem, but callousness toward civilians and misuse of authority are not just racial issues. And while reckless or callous police behavior is more likely to affect minorities and poor people of all races, “whiteness” and middle-class status are not protective shields.

The slogan “All lives matter,” used as a counterpoint to “Black Lives Matter,” has been endlessly mocked as a tactic to minimize police killings of black people. But incidents like Timpa’s death show that perhaps an “all lives” movement against police brutality is exactly what we need.

Cathy Young is a contributing editor to Reason magazine.