FLINT, Michigan (CNN) -- A few weeks ago, Nicole Mansfield called her daughter in Flint, Michigan. She tried to calm Triana Jones down, but she had bad news.
"She said, 'I might not be home in a week, somebody stole my ID,' " Jones recalled of the conversation almost a month ago. "So she wasn't able to come home."
This wasn't a minor headache, part of the travail of international travel. Jones thought her mother could be in Syria, fighting alongside rebels in the country's bloody civil war.
Nicole Mansfield had converted to Islam several years ago, her daughter told CNN Friday.
Jones wept as she and Gregory Mansfield -- her mother's father -- talked to CNN about the horror they felt seeing images on the Internet this week of a dead woman they are convinced is Nicole Mansfield.
Syrian state-run television aired a story saying that government forces had killed three Westerners. The video package shows a bullet-riddled car, weapons placed on the car hood, a computer, a hand-drawn map of a government military facility and a flag belonging to the al Qaeda-affiliated al-Nusra Front.
The camera pans close to bodies arranged in a row, lying on the ground. Mansfield's relatives told CNN they have no doubt she's one of them.
Though it's unclear how the family knew to look on the Web to see the images, they say the FBI paid the Mansfield family a visit Thursday to ask them about reports that Mansfield was killed in Syria.
"The first time I saw those pictures I had to look again because I didn't even recognize her. I didn't believe it was my mom the first time I saw them," Jones told CNN, choking back tears. "And then I had to look again and I looked at her body and her feet and her hands and her nose and her mouth. And I knew it was her."
Jones added that she's upset the pictures have gotten out, saying "I shouldn't have to see my mother's body like that all over the media and the Internet." She's also hurt by what people are saying about her mother -- like that she was a terrorist or a CIA agent.
"She was just an American woman who was misguided," Jones said. "... And it really makes me sick to my stomach that people post such horrible things." After showing the bodies, the Syrian television story shows shots of IDs; one of them appears to be Mansfield's.
Forces loyal to Syrian President Bashar al-Assad killed three Westerners, an announcer says. The story also shows a picture of a British man. The UK Foreign Office confirmed Friday that a British national was killed in Syria and officials are trying to reach relatives.
The United States is aware of the claim that an American woman was killed and is working through the Czech Republic mission in Syria to obtain more information, a State Department official told CNN on condition of anonymity.
Citing concerns that the privacy of a family could be jeopardized, the official declined further comment. CNN asked Jones why her mother might have wanted to go to Syria.
"I know that she was talking to people online and that they told her about the project in Syria," she answered. "And that she was interested in going over there to help. But she didn't think it would be fighting. She told me there wouldn't be (guns) or anything. She would never be involved in that."
"And they lied to her. They misled her and they took her and brought her over there, probably paid for her ticket and everything, and they kept her there."
CNN asked Jones if she could be more specific about what she meant by "project."
"That it was to help free the Syrians from the Syrian government and all the problems that they're having over there," she answered.
Nicole's father, Gregory Mansfield, contacted the FBI when his daughter left the United States three years ago, but he was not clear on where she went.
CNN asked Gregory Mansfield why he thought his daughter going abroad was disturbing enough to warrant notifying the FBI. He refused to explain. He said his worries concerned "Israel" and repeatedly insisted to CNN that the FBI should have revoked his daughter's passport.
Nicole's grandmother, Carole, said she last saw her granddaughter in Michigan in January. Another relative recently got a call from Nicole Mansfield in which she said she was gone, but she'd be back to the United States for a visit soon.
Carole Mansfield and Monica Steelman, Nicole's aunt, described Nicole as caring and outgoing, saying she'd sometime travel without telling her family where she was heading. She had worked as a home care worker and had been married twice, including to a man who practiced Islam.
"Nicole was the type of person if she thought that something was wrong somewhere, that she could help repair it," said her aunt.
Her niece tried to be a "problem solver," she said.
"Trouble spots," Carole Mansfield said, "... fascinated her."
Raised Christian, she converted to Islam three to five years ago and used to worship at a mosque in Flint. Carole Mansfield said she spoke to her granddaughter after her conversion.
"At that time I told her that I thought she was looking a rattlesnake in the eyes," the grandmother said. "But that's my belief. Not that I felt it made her a bad person."