Following a brutal attack on a German train on July 18 by an ax- and knife-wielding teenager who was an Afghan refugee, the Islamic State (ISIS) claimed responsibility for the attack. Four people were injured in the attack, one critically. The attacker, identified in an ISIS video as Muhammad Riyad, reportedly shouted the Islamist slogan “Allahu akbar” (“God is great”) during the assault, which took place in the German city of Wurzburg. The ISIS-linked online Amaq news agency said Riyad was an ISIS “fighter.” The Amaq statement said: The perpetrator of the stabbing attack in Germany was one of the...