Tensions and background
For several months leading up to the attack, tensions had been building up in the area, particularly between Yazidis and Sunni Muslims (Muslims including Arabs and Kurds). Some Yazidis living in the area received threatening letters calling them "infidels". Leaflets were also distributed denouncing Yazidis as "anti-Islamic" and warning them that an attack was imminent.
The attack might be connected to an incident wherein Du’a Khalil Aswad, a 17-year-old Yazidi girl, was stoned to death by the Yazidis. Aswad was believed to have wanted to convert in order to marry a Sunni. Two weeks later, after a video of the stoning appeared on the Internet, Sunni gunmen stopped minibuses filled with Yazidis; 23 Yazidi men were forced from a bus and shot dead.
The Sinjar area which has a mixed population of Yazidis, Kurds, Turkmen and Arabs was scheduled to vote in a plebiscite on accession to the Kurdish region in December 2007. This caused hostility among the neighbouring Arab communities. A force of 600 Kurdish Peshmerga was subsequently deployed in the area, and ditches were dug around Yazidi villages to prevent further attacks.