A young Yazidi woman testified on Monday that American aid worker Kayla Mueller told her she was raped by former Islamic State leader Abu Bakr al-Baghdadi and threatened with death if she tried to escape.
Lia Mulla, who was captured by Islamic State (IS) members in August 2014 as she tried to flee Iraq's Mount Sinjar with her family, testified through a translator on Monday at the trial of El Shafee Elsheikh, who was allegedly one of Mueller's IS jailers.
Elsheikh, a 33-year-old former British national, is accused of being a member of the notorious IS kidnap-and-murder cell known as the "Beatles."
He is charged with the murders of four Americans: Mueller, freelance journalists James Foley and Steven Sotloff and Peter Kassig, another relief worker.
Mueller, an aid worker from Arizona, was captured by IS in August 2013 while accompanying her Syrian boyfriend on a trip to a hospital in Aleppo, where he was contracted to repair a satellite dish.
She was initially held by the "Beatles" but then was allegedly turned over to Baghdadi, the IS leader who died during a U.S. special forces raid in 2019.
Mulla said she was taken by IS to various locations with other young women after being captured.
Eventually, she ended up in a prison where Mueller was being detained.
They communicated "mostly with their hands," she said, and a few words of Arabic.
"One day they took her and when they brought her back she was really afraid," Mulla said. "They had told her that IS wanted to marry us off, and if we were to try to run away they would kill us."
A couple of days later, Mulla said she was taken along with Mueller and another Yazidi girl to the home of Abu Sayyaf, a top Baghdadi lieutenant, where they would "treat us like slaves."
After a week there, she said they were taken to the "dirty house... the place where they took young girls and raped them."
She said Baghdadi came one night and took Mueller away.
When Mueller returned the next morning, "she was very sad, she was very nervous, she was crying," Mulla said. "She had been raped and threatened that if she tried to run away he would kill her."
Mulla said she decided to try to escape and asked Mueller to join her but she declined.
"She was afraid that if she was captured, she would be beheaded," she said.
But Mueller asked Mulla to "tell the world" about her if she managed to make it to freedom.
Mulla said she slipped out a window, climbed on a generator to get over a wall and ran for a long time.
After her escape, she said her brother put her in touch with a friend who was a translator for the Americans and she told them about Mueller.
IS announced Mueller's death in February 2015 and said she was killed in a Jordanian airstrike, a claim that was disputed by U.S. authorities.
Foley, Sotloff and Kassig were murdered by IS and videos of their deaths released by the group for propaganda purposes.
Elsheikh and another "Beatle," Alexanda Amon Kotey, were captured in January 2018 by a Kurdish militia in Syria and turned over to U.S. forces in Iraq.
They were flown to Virginia in 2020 to face charges of hostage-taking, conspiracy to murder U.S. citizens and supporting a terrorist organization.
Kotey pleaded guilty in September 2021 and is facing life in prison.
"Beatles" executioner Mohamed Emwazi was killed by a U.S. drone in Syria in 2015.
Prosecutors are expected to wrap up their case against Elsheikh on Tuesday.
Elsheikh has denied the charges and his lawyers claim his arrest is a case of mistaken identity.