To the German authorities, he was Mohammad Daleel, a 27-year-old Syrian traumatized by war who arrived in Europe seeking refuge.  To the Islamic State, he was Abu Yousef, a jihadist who went to Europe for medical treatment after being wounded, intending to return to battle.

Nearly two weeks after he became Germany’s first suicide bomber, detonating a backpack filled with chemicals and sharp metal bits outside a music festival in the southern town of Ansbach, his actual identity and motives remain unclear.  That fact has raised troubling questions about the refugee policies of Chancellor Angela Merkel as Germany works to integrate nearly a million migrants and she faces calls for a firmer approach, led by a surging far right.

Read more: New York Times