Kayla Mueller was kidnapped by ISIS while illegally in Syria and made a sex slave. She was tragically killed in an airstrike before her family was able to free her for the ransom demanded by ISIS. While she is commonly presented by the media as a humanitarian "aid worker", there is more to her story. In fact, she was far more of an "activist" than a true aid worker. She was illegally in Syria and unexpectedly showed up at a hospital operated by Doctors Without Borders - not to provide "aid", but to accompany her Syrian boyfriend who had been contracted to perform IT repairs at the hospital. The hospital immediately made arrangements to return her to Turkey the next day, but she was kidnapped at the bus station.
Ultimately, Mueller was the tragic victim of an idealistic, faulty worldview. Her efforts led her to Syria, where ISIS took her hostage and sold her to a militant commander for a sex-slave war trophy. She paid a heavy price for her worldview.