Three years of war in Sudan have left over 8,000 people missing, according to the International Committee of the Red Cross.
Many disappeared while fleeing as refugees or during clashes.
Most of the missing in Khartoum state are believed to be buried in unmarked graves. After the army regained control of the capital last year, tens of thousands of bodies were found.
During the fighting, burying the dead in cemeteries was often too dangerous, so people dug graves wherever they could.
AP reporters witnessed football fields and abandoned gas stations littered with makeshift graves bearing names and dates, but many remain unidentified.
