None in the crowd stepped forward, said a witness to the event in a northern Syrian city. So the jihadi fighters, mostly foreign extremists, did it themselves, pelting Faddah Ahmad with stones until her body was dragged away.

“Even when she was hit with stones she did not scream or move,” said an opposition activist who said he witnessed the stoning in the city of Raqqa, the main Syrian stronghold of the Islamic State group.

The July 18 stoning was the second in 24 hours. A day earlier, 26-year-old Shamseh Abdullah was killed in a similar way in the nearby town of Tabqa by Islamic State fighters. Both were accused of having sex outside marriage.

The killings were the first in rebel-held northern Syria, where jihadis from the Islamic State group have seized large swaths of territory.