Kayla Mueller, the US hostage who died at the hands of Islamic State earlier this year, became a sex slave to ISIS leader Abu Bakr al-Baghdadi according to US officials.

The officials confirmed a report by ABC News, which said Mueller's family had been told by U.S. government officials that their daughter, who was 26 at the time of her death, had been sexually assaulted by al-Baghdadi. The officials spoke to Reuters on the condition of anonymity. The White House declined to comment. "We were told Kayla was tortured, that she was the property of al-Baghdadi. We were told that in June by the government," Kayla's parents, Carl and Marsha Mueller, were quoted as telling ABC News. Islamic State said in February that Mueller, of Prescott, Arizona, was killed when Jordanian fighter jets bombed a building where she was being held outside Raqqa, a stronghold in Syria of the Islamist militant group. Jordanian and U.S. officials have expressed doubt about Islamic State's account of her death following 18 months as a hostage. Mueller was taken hostage in August 2013 while leaving a hospital in Aleppo in northern Syria. Al-Baghdadi personally brought Mueller to be imprisoned inside the home in Syria of Abu Sayyaf, a Tunisian Islamic State figure who was killed in a U.S. raid in May, counter-terrorism officials told ABC News over the past several months. The information about al-Baghdadi's role in the captivity and sexual abuse of Mueller was drawn from many sources including U.S. interviews with at least two teenage Yezidi girls held as sex slaves in Sayyaf's compound and the interrogation of Sayyaf's wife, Umm Sayyaf, who was captured by U.S. forces in the raid in which her husband was killed, ABC News quoted the officials as saying.

This will probably shock a lot of Americans, but it shouldn't. In its attempt to revive the caliphate, Islamic State is using the Koran to justify practices that haven't been seen for more than 1000 years. The grisly executions, the rapes, the establishment of a slave market - these are all being justified by ISIS as teachings from the Koran.

Beyond that, Islamic State is telling its fighters that raping non-Muslim women makes them holy. The New York Times published a searing account of the travails of Yazidi women captured by ISIS in the fight for Mt. Sinjar:

The systematic rape of women and girls from the Yazidi religious minority has become deeply enmeshed in the organization and the radical theology of the Islamic State in the year since the group announced it was reviving slavery as an institution. Interviews with 21 women and girls who recently escaped the Islamic State, as well as an examination of the group’s official communications, illuminate how the practice has been enshrined in the group’s core tenets. The trade in Yazidi women and girls has created a persistent infrastructure, with a network of warehouses where the victims are held, viewing rooms where they are inspected and marketed, and a dedicated fleet of buses used to transport them. A total of 5,270 Yazidis were abducted last year, and at least 3,144 are still being held, according to community leaders. To handle them, the Islamic State has developed a detailed bureaucracy of sex slavery, including sales contracts notarized by the ISIS-run Islamic courts. And the practice has become an established recruiting tool to lure men from deeply conservative Muslim societies, where casual sex is taboo and dating is forbidden. A growing body of internal policy memos and theological discussions has established guidelines for slavery, including a lengthy how-to manual issued by the Islamic State Research and Fatwa Department just last month. Repeatedly, the ISIS leadership has emphasized a narrow and selective reading of the Quran and other religious rulings to not only justify violence, but also to elevate and celebrate each sexual assault as spiritually beneficial, even virtuous. “Every time that he came to rape me, he would pray,” said F, a 15-year-old girl who was captured on the shoulder of Mount Sinjar one year ago and was sold to an Iraqi fighter in his 20s.

As ISIS ideology and theology becomes more popular, the problem of getting rid of them becomes more difficult. As with the confrontation between Nazism and communism and the west, in order to defeat an idea, you have to offer a better idea. And it's becoming frighteningly clear that those in the west who stood tallest when confronting those twin evils - artists, intellectuals, and other public thinkers - don't have the stomach today to confront anything.