Experts from the World Health Organisation (WHO), along with members of the the Organisation for the Prohibition of Chemical Weapons, (OPCW) have been trying to ascertain what substance was used in Tuesday's deadly chemical attack in Syria's Idlib province.
They arrived in Turkey several days ago and have been carrying out extensive tests on the bodies of some of the victims.
WHO said initial indications were that the nerve agent Sarin was used.
Family members of the victims are hoping for answers. More than 70 people were killed and hundreds were injured in the attack carried out by regime war planes.
Some of the injured, most of them women and children, were brought to Turkey for treatment.
TRT World's Shamim Chowdhury reports from Hatay, on the Turkey-Syria border.