Ashwaq was only 14 when Islamic State fighters stormed into northern Iraq, including the heartland of the Yazidi people. They took thousands of women as sex slaves, including Ashwaq - sold for $100 to a man named Abu Humam. Raped and beaten, she managed to escape three months later and then went to Germany with her mother and one brother. A few months ago, on the street outside a supermarket, she heard someone call out her name. She says it was Abu Humam - and he said he knew where she lived. Düzen Tekkal, an activist and the founder of...