(Photo: Justin Sullivan/Getty Images)

When a white police officer fatally shoots a black man, angry acquaintances often assume the tragedy was triggered by a racist cop.

New research reports that, while some officers may by driven by personal prejudice, the bias that can serve as a catalyst for killings is more institutional than individual.

"White officers do not kill black suspects at a higher rate compared with nonwhite officers," concludes a research team led by Charles Menifield, dean of the School of Public Affairs and Administration at Rutgers University–Newark. "The killing of black suspects is a police problem, not a white police problem."

Menifield and his colleagues constructed a database of all confirmed incidents in which deadly force was used by police in the United States during 2014 and 2015. It includes detailed information on both the officer and victim.

Not surprisingly, they found a huge racial disparity when it comes to who gets killed by officers. "While only about 13 percent of the American population is black," they write, "28 percent of people killed by police are black."

The victims were overwhelmingly male (95.5 percent), and less than 1 percent were unarmed at the time of the incident. "The gun could been in the car, or on them, but it was there at the time they were killed," Menifield noted.

The majority of officers in these situations were white. But this reflects the fact that America's police forces are disproportionately made up of whites, who account for approximately three-quarters of all officers.

Crunching the numbers, the researchers report "white police officers actually kill black and other minority suspects at lower rates than we would expect if killings were randomly distributed among officers of all races."

In contrast, "we find that nonwhite officers kill both black and Latino suspects at significantly higher rates than white officers," they write. "This is likely due to the fact that minority police officers tend to be assigned to minority neighborhoods, and therefore have more contact with minority suspects."

But if individual-level racism isn't the issue, what is? Menifield and his colleagues make a strong argument that the fundamental problem is one of institutional culture.

"We believe that the disproportionate killing of black suspects is a downstream effect of institutionalized racism ... within many police departments," they write. At least in part, "disproportionate killing is a function of disproportionate police contact among members of the African-American community."

In other words, if a certain percentage of such encounters between the police and public end in tragedy, and cops are more likely to come into contact with black citizens (for instance, ordering African-American drivers to pull over at higher rates than whites), it stands to reason that black civilians are at greater risk of ending up dead.

Blaming racist cops for this problem is emotionally satisfying (it presents a clear villain) and suggests an easy fix (weed them out). But this research suggests the real problem is the entrenched set of biases and assumptions that pervade police forces, influencing the attitudes and actions of cops of all colors.