A young Yazidi sex slave told The Daily Mail that Islamic State (ISIS/ISIL) militants ripped off American hostage Kayla Mueller’s fingernails before she became the wife of leader Abu Bakr al-Baghdadi.

“When they first captured Kayla, ISIS fighters pulled her nails out,” said Muna, 16. “She was forced to convert to Islam.”

ABC News reported in August that al-Baghdadi brought Kayla Mueller to the house of Abu Sayyaf, his best friend and the man in charge of the terrorist group’s oil revenue. Al-Baghdadi took her as his “wife” and repeatedly raped her, even in front of the Yazidi sex slaves.

“She was afraid and she didn’t resist as he would beat her,” explained Muna. “I saw him rape her three or four times and they told us that anybody who runs away, including Kayla, would be killed… Kayla did not know she was the Caliph, but she knew he was important. When Kayla returned in the morning she was crying and said she’d been raped.”

Al-Baghdadi chose Muna “from 61 Yazidi women and girls aged between nine and 22 who were among the hundreds taken hostage during last year’s devastating siege of Mount Sinjar.” He took her to his house in Raqqa to live with his other wives and children.

“The wives were always worse than Baghdadi,” she claimed. “They were always telling the children that they were lazy and beating them.”

Muna attempted one escape, but al-Baghdadi’s thugs caught her. She said the man “beat her all over her body with a belt and garden hoe” and hit her face “until her nose bled.” He also slapped her face with “cables and wooden sticks.” One beating resulted in a dislocated shoulder.

That is when he took her to a prison in Raqqa, which is where she met Kayla Mueller and Yazidi sex slaves. She told The Daily Mail she and the other slaves planned an escape. A 14-year-old relayed a similar story to The Independent in August.

Mueller risked her life to protect the Yazidis. The teenager escaped with her sister in October, but Mueller decided to stay behind because she thought “her foreign appearance would put them in danger while on the run.”

“Kayla tried to protect these young girls,” said Marsha Mueller, Kayla’s mother. “She was like a mother figure to them.”

U.S. forces in Syria arrested Umm Sayyaf, the organizer of the sex slave trade, in May. She allegedly is cooperating, and the White House did state she would “be prosecuted in Kurdish Iraq and would be ‘held accountable for her crimes.’”

ISIS captured Kayla Mueller in August 2013. The jihadists claimed an airstrike by Jordan killed her, but they have only published a photo of rubble in Syria as proof of her death. A few days later, however, her parents in Arizona confirmed her death. ISIS sent them pictures to prove she was deceased. Officials told ABC News that no one truly knows how Mueller died.

In February, The Daily Beast reported that President Obama waited almost a month after British intelligence told him the location of American hostages to launch a rescue mission. President Obama received the reports in June 2014, but by the time he acted on July 4, ISIS had already moved the hostages, which included Kayla Mueller, James Foley, and Steven Sotloff, to another location. ISIS executed Foley and Sotloff in August and September, respectively.