It should be easy to tell the difference between an aid worker and a jihadist, but the war in Syria shows that is not always the case. Finding a solution could help ensure aid still reaches the people who need it in future conflicts.
A desire to ease the suffering of ordinary Syrians during its years of civil war has been shared by many people around the world.
But getting aid into Syria and making sure it reaches the right people is extremely difficult.
The conflict is complex and jihadists took advantage of the ensuing confusion – particularly at the start of the war – with some aid money diverted and foreign fighters entering the country by posing as aid workers