The Demographics of Genocide: Who Commits Mass Murder?

New research reveals that perpetrators of the genocide in Rwanda were most likely to be males in their mid-thirties.
By Avital Andrews,
(Photo: Shutterstock)

Given that genocide has killed more people during the 20th century than every other type of crime combined, you’d think more people would be studying it.

The problem has been that, until recently, social scientists thought genocide was random and therefore could not be understood.

“A few decades ago, however, scholars began to realize that, like other social phenomena, genocide is patterned and socially structured,” says Hollie Nyseth Brehm, a sociologist at Ohio State University. “After the Holocaust, leaders around the world vowed to prevent genocide from happening again. Yet genocide continues to occur, taking millions of lives, forcing many more to leave their homes, destroying cultures, and causing other social harm.”

"We were surprised that perpetrators of genocide in Rwanda were, on average, 34 years old. Much research in criminology would point toward much younger participants—late adolescence and early twenties—in most any form of crime."

While interning with Rwanda’s genocide prevention commission, Brehm obtained access to the country’s court records. Those records hold information about who participated in that country's 1994 genocide, which killed more than one million Tutsis in just a few months. She gathered a few colleagues—assembling the only team in the world with access to this data—and took a couple of years to analyze more than one million Rwandan convictions.

“We were surprised that perpetrators of genocide in Rwanda were, on average, 34 years old," Brehm says. "Much research in criminology would point toward much younger participants—late adolescence and early twenties—in most any form of crime.”

The team also found that men between the ages of 18 and 45 were responsible for 75 percent of the Rwandan atrocities, representing a demographic slice that does not reflect the age or gender distribution of Rwanda’s larger population. (It's worth noting that more than 10 percent of Rwanda’s population took part in inflicting the genocide, compared to a 0.0097 percent homicide rate in America in 1994.)

In the paper detailing their findings, Brehm and her colleagues posit that this population might be more likely to commit genocide because “perpetrators often believe they are acting to protect their family or nation from outsiders who are dangerous or even subhuman” and that “violence has been framed as ‘work,’ which has age-graded overtones and a clear link to adult role behavior.” Accordingly—and consistent with other forms of crime—the likelihood of being a genocide perpetrator declines significantly after middle age.

The full study, titled “Age, Sex and the Crime of Genocide,” is under review for publication, though Brehm has presented its results at conferences.

Brehm emphasizes that there is much more work to be done to fully understand genocide’s risk factors. “We are hopeful," she says, "that learning more about who commits genocide may be useful in targeted interventions."

Rosie Spinks contributed reporting.