Kayla Mueller stood before her boyfriend in a Syrian detention cell, faced with a question that could have secured her freedom from Islamic State militants.

"Why are you telling them you are not my wife?" Omar Alkhani asked Mueller before she broke down in tears.

"I don't know," she said.

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 to show she was the American hostage from Prescott, Arizona.

The guards told Mueller, 26, that Alkhani would not be harmed if she told the truth, so she apparently stuck to honesty to save him rather than take the slim chance to save herself, he said.

"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."

Thinking about others first was Mueller's nature. She had long been content without spending the wages she earned as an international aid worker on new clothes, a hair dryer or makeup so she could use her money to help others instead, Alkhani said.

The Syrian spoke to The Associated Press on Sunday via webcam from Turkey in one of his first interviews, detailing how he met Mueller in 2010 and the last time he saw her in 2013 as a prisoner of the Islamic State group.

The U.S. government and Mueller's family confirmed her death last week. In the days since, hundreds of people have gathered to honor her in her hometown and in Flagstaff, where she attended Northern Arizona University.

Mueller and Alkhani were taken hostage in August 2013 after leaving a Doctors Without Borders hospital in Aleppo, Syria, where he was hired to fix the Internet connection. Mueller had begged him to let her tag along so she could see the suffering firsthand and help, despite the dangers of traveling into the war-torn region. He said he agreed reluctantly.

"We argued about it," he said. "In the end, I was afraid if she didn't go with me, she would go with someone else."

Mueller took advantage of an unexpected overnight stay at the hospital when the repairs took longer than expected and asked Syrian women about how they managed daily life. During what should have been a 10-minute trip to the bus station the next day, Mueller, Alkhani, the taxi driver and a fourth person were ambushed by six masked men with automatic rifles and threatened with death.

"`Maybe it's a mistake,"' Alkhani said he told Mueller, who was afraid and shaking. "`Please be strong until we find somebody to talk to."'

Mueller remained a hostage, while Alkhani said he was released 20 days later after being beaten and interrogated about his work as a photographer, his religion and his relationship to Mueller.

His captors told him to forget about Mueller and his camera equipment, he said.

Against the advice of his friends, Alkhani said, he returned to Syria from Turkey later in 2013 to try to get back the woman he met three years earlier in Cairo after she responded to an advertisement he posted to house international visitors.

Mueller stayed less than a week in Cairo, but Alkhani said they quickly bonded and kept in touch through the Internet and traveled together, discussing ways they could change the world. They became a couple, and he said he promised her that he would always look out for her.

While she was in France learning the country's language to go to North Africa, Mueller encouraged Alkhani to follow his dream of helping fellow Syrians. She eventually joined him in Turkey near the Syrian border where she saw people living in the streets and standing in line for hours to get food.

She solicited donations from whomever she could to buy a wheelchair for a handicapped boy, pay rent for a family or get sewing machines so women could start a clothes-making business, Alkhani said.

"She didn't come to tell people there are tanks in the street -- everybody knows," Alkhani said. "She came to find a young lady in the garden who can't find a place to sleep, tell people that there's a human here."

Alkhani said he had spoken to her often about Syria, where bloodshed has gripped the country under the regime of embattled President Bashar Assad, and sent her recordings, photographs and other information that she used for her blog. Nearly half of Syria's population has been displaced, and some 200,000 people have died in the fighting.

"She wanted everyone to use their freedom to help us get freedom," he said.

When they were captured together and detained, Alkhani said he at least had some reassurance she was alive. He would cough or say something to make sure his voice was heard, and she sometimes would cough in return. Other times, he or his cellmates would peer under the door and see the sandals she was wearing, he said.

Alkhani said he learned that Mueller was being held in the industrial area of the Aleppo suburbs. When he finally arrived at the lockup, he said he was given the opportunity to ask Mueller himself if they were married. He moved past a couch surrounded with body guards and saw her, seemingly in good health.

"At least I tried," he said. "My conscience, I can't say I'm OK with my conscience, because I put her in this in the beginning. If I refused to take her with me, this wouldn't have happened."

Alkhani said he has been in touch with Mueller's family and held out hope like they did during her 18 months of captivity that she was alive. He thought, maybe the militants would release her recognizing that she was only in Syria to help people, he said.

"I didn't realize one day I will receive this call from somebody telling me, `I am sorry,"' he said.

A spokesperson for Mueller's family said they have no reason to not trust Alkhani's account, and the family believes he loved her and tried to help her. The spokesperson talked to the AP on condition of anonymity because the person works in media relations for other families in Middle East hostage situations and wants to remain anonymous for safety reasons.