Kayla Mueller was in a detention cell in Syria, face to face with her boyfriend who was posing as her husband. Had she told her captors she was married to Omar Alkhani, she might have been freed from the hands of Islamic State militants, he said. Instead, she denied being his wife.

Her death was confirmed last week by the US government and Mueller's family.

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