Before her death earlier this year, 26-year-old Kayla Mueller was a sex slave for the top leader of the Islamic State, the American aid worker's parents have revealed.
In a Friday interview with ABC on what would have been Kayla's 27th birthday, her parents said that they were informed by government officials that their daughter was repeatedly raped by the caliph of the Islamic State, Abu Bakr al-Baghdadi.
ISIS announced Kayla's death on February 10, claiming that the aid worker from Prescott, Arizona had been killed in an coalition airstrike.
However, ISIS was aware that the U.S. was working to rescue Kayla and the true circumstances of her death are not known.
'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, said.
American officials allegedly learned about Kayla's abuse, after interviewing two Yezedi girls, 16 and 18, who escaped from the same compound where they were all held as sex slaves.
According to the escaped girls, Kayla was held in the home of Abu Sayyaf, a Tunisian man in charge of ISIS' oil and gas revenue.
That was confirmed by Sayyaf's wife, Umm Sayyaf, who was captured in a U.S. raid of the compound.
The caliph is said to have regularly visited the house to both speak to Sayyaf and rape Kayla.
The new information on Kayla's abuse at the hands of ISIS's top leader discredits reports that Kayla warmed to her captors and had even willingly married a member of the state.
Those reports started when the Muellers received a smuggled letter from their daughter a year into her captivity, that read: I am 'completely unharmed and healthy (put on weight in fact); I have been treated w/the utmost respect and kindness.'
Kayla was abducted in August 2013, while working in southern Turkey with Syrian refugees. On August 3, she drove a friend into the bombed-out Syrian city of Aleppo and was driving back when she was taken hostage. She spent two and a half years as a prisoner of the Islamic State, before her mysterious death.
The U.S. became aware of Kayla's whereabouts in the Islamic State last year, when a Yezedi girl escaped from the Sayyaf compound and was intercepted by U.S. agents.
The military then mounted a plan to raid Sayyaf's compound to rescue Kayla.
American officials have maintained a policy of not naming U.S. hostages in the media, so as not to entice ISIS to publicly torture or murder them for publicity.
But White House Chief of Staff Dennis McDonough accidentally dropped Mueller's first name in a television interview on January 25, bringing renewed attention to her case.
President Obama was then forced to answer what the U.S. was doing to help Kayla on February 1, saying: 'What we can say is that, as has been true of all the hostages, that we are deploying all the assets that we can working with all the coalition allies that we can to identify her location. And we are in very close contact with the family trying to keep them updated.'
Nine days later, ISIS announced that Kayla had been killed in a coalition strike. The Pentagon maintains that she was murdered by her captors.
While they weren't able to save Kayla in time, U.S. forces did eventually mount an attack on Sayyaf's compound.
The elite Delta Force team raided the Syrian compound in May, and killed Sayyaf while taking into custody his wife and a treasure trove of ISIS intelligence.
Umm Sayyaf gave extensive information to American interrogators and has been turned over to the Iraqi Kurds for trial. The Muellers have been told she can be expected to serve a long prison sentence, Mueller family spokesman Emily Lenzner said.
However, Sen John McCain,of the Mueller's home state of Arizona, wrote to Attorney General Loretta Lynch on Thursday, demanding an explanation for why Sayyaf was handed over to the Kruds and not brought back to the U.S. for trial.
In his letter, McCain wrote that he was 'deeply concerned' as to why Umm Sayyaf had not been extradited back to the U.S., since she 'was clearly involved at the top levels of a foreign terrorist organization' and 'complicit' in Kayla's captivity.
Mueller's death hits close to home for McCain, not only because she was a resident of his state, but because he too was held as a prisoner of war for more than five years during the Vietnam War.