In 2015, a Yazidi woman, who escaped from Islamic State militants, carried water at Sharya refugee camp on the outskirts of Iraq’s Dahuk province. (Ari Jala/Reuters)

Three years ago this month, the Islamic State started a systematic attack against the Kurdish-speaking Yazidi minority based in the Sinjar area of northwestern Iraq. We now have a better understanding of the militant group’s patterns of violence and goals because of the discovery of mass graves, survivor testimonies and the Islamic State’s public declarations.

This new evidence tells us that while the Islamic State’s extremist ideology provided the guiding principle, large numbers of locals with varying motives actively participated in these atrocities. The pursuit of material gains and stigmatization of the Yazidis as a marginalized religious minority have been the driving factors of the violence at the local level.

The precarious existence of the Yazidis

While many other ethnoreligious groups in northern Iraq have been subject to various degrees of Islamic State violence, the treatment of the Yazidis at the hands of the group amounts to what human rights organizations deem genocide: including mass executions and abductions, sexual enslavement and forced conversions. Out of an estimated 400,000 Yazidi people living in Sinjar, at least 10,000 were either killed or abducted. Almost the entire population is displaced.

The Yazidis, an insulated and internally hierarchical community, have a long history of persecution and victimization at the hands of Muslim rulers and extremist organizations. While the Yazidis have lived among Sunni Arabs and Kurds side by side for centuries, discriminatory practices and social distance characterized interreligious relations, including the widespread perception that Yazidis are devil worshipers. In the aftermath of the 2003 invasion of Iraq, many Yazidis gained new employment opportunities under the de facto Kurdish control over the area that generated resentment among local Arabs.

The Islamic State’s ideology and Yazidis

In this historical context, the rapid advance of the Islamic State into the Sinjar area became a disaster for the Yazidis. The Islamic State’s ideology defines the Yazidis as polytheists who have no right to exist under Islamic rule. In many instances, captured Yazidis were given the “choice” of conversion or death and enslavement.

In 2014, a large village about 15 miles south of Sinjar called Kocho held off Islamic State fighters in a siege that lasted 12 days. As recounted by a survivor, eventually, the Islamic State fighters stormed the village and massacred about 400 men immediately and about 80 elderly women later. The remaining women and children were treated as slaves and sold to Islamic State fighters. Even while the Islamic State took pains to say that it prohibited gang rape — as Yazidi women were supposed to be the exclusive property of their owner — Islamic State fighters simply sold their “slaves” to other fighters.

From neighbors to perpetrators: Looking beyond ideology

A recent study shows that perpetrators’ ideology often plays a decisive role in their choice of targets and means of violence. At the same time, one needs to look beyond ideology to opportunism and deep-rooted stigmatization of the Yazidi minority to explain how the Islamic State’s violence against that community faced no opposition from the local population.

A recurrent theme in my conversations with Yazidis and testimonies of female survivors is that not only foreign fighters but also local Iraqis and Syrians, both men and women, were actively involved in their rape and enslavement. In the words of a survivor, “They did not attack us because of their ideology, but to simply have the opportunity to rape us.”

While some Sunnis from the Sinjar area tried to protect their Yazidi neighbors, many others, including godfathers of Yazidi boys who were supposed to act as their protectors, participated in the enslavement of women and the robbing of the Yazidis and looting of their properties resulting in revenge attacks after the defeat of the Islamic State. The mass abduction of Yazidis has become a profitable activity for both the local population and Islamic State fighters, who often sold their captives back to their families for hefty sums via smugglers.

It is too simplistic to argue that the Yazidi tragedy is a direct and inevitable result of historical religious antagonisms. Yet, even if many of these locals did not subscribe to the Islamic State ideology and were not its members, they readily dehumanized the Yazidis after the ascendancy of the Islamic State. Deep-rooted stigmatization of Yazidis and general insecurity in post-Saddam Hussein Iraq contributed to their vulnerability as a community and enabled the Islamic State to implement its exterminating ideology and find collaboration among the local population.

This pattern of genocidal political projects mobilizing ordinary people in mass crimes has been observed in settings as diverse as Nazi Germany and Rwanda. The uniqueness of the Islamic State ideology should not obscure the fragility of intercommunal coexistence in times of crises and the difficulty of intercommunal reconciliation.

Güneş Murat Tezcür is the Jalal Talabani chair of Kurdish Political Studies and directs the Kurdish Political Studies Program at the University of Central Florida.