AL-TLEILIYE, Syria — A raised metal bed stands in a yard. The stench of rotting flesh chokes the air. A man in fatigues points to traces of blood blotting the earth, saying, “Women, children, they murdered them in their sleep. They even killed the dog; that’s what causing the smell.”

Djvar Osman is a commander for the People’s Protection Units (YPG), the Kurdish militia that controls a band of mainly Kurdish-populated territory in northeastern Syria they call Rojava. We are in al-Tleiliye, a tiny village close to the Turkish border that was raided May 29 by the Islamic State of Iraq and al-Sham (ISIS).

The jihadists shot dead 15 civilians, many as they slept outdoors, in what appears to have been a retaliatory attack against the YPG. One of the victims, Mohammed Mahmoud Hossain, was only a year old. All were Sunni Arabs, apparently mistaken for the village’s original occupants, Kurdish-speaking Yezidis, who are doubly targeted because of their syncretic faith. 

As YPG commanders ponder the dizzying gains of ISIS in neighboring Iraq — the group captured the city of Mosul on June 8 — an Arab farmer in a hamlet outside al-Tleiliye stiffens when approached by a journalist. He survived the bloodbath, but his brother did not. “I cannot say more,” he rasps, pulling an imaginary zipper over his mouth. He walks toward a concrete hut, its walls covered in a crude Arabic scrawl. “We have come to slaughter you. It's forbidden for Jabhat al-Nusra to approach,” it reads.