Where are Raqqa’s missing? Families of thousands captured by ISIS on a mission to find out their fate

She had expected to feel some sense of relief when her hometown of Raqqa was liberated from Islamic State last week.

But 23-year-old Leila al-Khalek was just left feeling empty.

She thought that with the fall of the northern Syrian city would come the answer to a question that has consumed her for almost four years: Where was her father?