Officials: ISIS leader sexually abused U.S. hostage..

ISIS leader Abu Bakr al-Baghdadi sexually abused American hostage Kayla Mueller while she was in captivity, U.S. government officials said.

A spokeswoman for Mueller's family --who learned she was dead in February -- confirmed the information to CNN.

We were told Kayla was tortured, that she was the property of al-Baghdadi. We were told that in June by the government," the family told ABC News.

The family spokeswoman noted that Friday would have been Mueller's 27th birthday.

Mueller's treatment at the hands of the ISIS leader was first reported by The Independent and ABC News.

Details of the reports were confirmed to CNN by multiple sources, including the family representative.

Al-Baghdadi was personally involved in arranging for Mueller to be held in the home of a senior ISIS leader, Abu Sayyaf, after the American was captured in northern Syria in 2013. Sources say the ISIS leader would go to Sayyaf's house where he would sexually abuse Mueller, a humanitarian worker from Prescott, Arizona.

Kayla Mueller graduated from Northern Arizona University in 2009 and worked with humanitarian groups in northern India, Israel, the Palestinian territories and Syria, a family spokeswoman said.

Two Yazidi girls -- members of a small Iraqi minority group that have been among those persecuted by ISIS -- who also were held in Sayyaf's compound gave the U.S. government information about what happened there.

ISIS claims the Quran justifies taking non-Muslim women and girls captive, that they can be sold as "property," and that rape of captive women is permissible. ISIS spelled out that doctrine in a pamphlet, "Questions and Answers on Female Slaves and their Freedom," distributed after the group seized the Iraqi city of Mosul.

While al-Baghdadi remains the Islamist extremist group's top figure, Abu Sayyaf himself is no longer in the picture, having been killed by U.S. Special Forces in a raid last May.

Source : CNN