Kayla Mueller: Boyfriend of US hostage 'tried to free her' while she was being held by Isis

Alkhani said he posed as her husband in the hope that the Isis militants would free her

(EPA)

The boyfriend of US hostage Kayla Mueller has told of how he made an effort to free her while she was being held in Syria by Isis.

Mueller, 26, was taken in August 2013 after driving into the northern Syria city of Aleppo with boyfriend Omar Alkhani, after leaving a Doctors Without Borders hospital where he had been working.

Her colleagues received subsequently received a proof-of-life video, showing her wearing a hijab and begging for her life.

"Since she's American, they would not let her go anyway. No sense to stay here, both of us," Alkhani said. "Maybe she wanted to save me. Maybe she didn't know I came back to save her."

The guards had told Mueller that Alkhani would not be harmed if she told the truth. He suggested that she chose honesty to save him rather than take a chance to save herself.

Alkhani said he had persuaded a string of people to let him plead for her release, but left the room empty-handed. He said he saw Mueller’s face for just a few seconds when guards uncovered it to prove it was her.

A spokesperson for Mueller's family said they didn't have any reason not to trust Alkhani's account.

"They know that he deeply cared for her, and when he went back to try and rescue her by posing as her boyfriend, they knew he was taking extreme risks to do that," the spokesperson said.

A week after Isis militants claimed that the aid worker had died in a Jordanian airstrike, Mueller’s family, who live in Prescott, Arizona, confirmed she had lost her life.

The Pentagon has said it does not know how she died, but said it is certain it was not during the airstrike.

The US government and Mueller's family confirmed her death on 10 February 2015.

Additional reporting by AP