BURTON, Mich. – A Michigan mother killed during fighting in Syria often left many family members and friends in the dark about the details of another life — marrying an Arab immigrant, moving around frequently and taking trips to the Middle East, including the one that would be her last, relatives said Friday.

An aunt and the grandmother who raised Nicole Lynn Mansfield say they are left with differing, incomplete accounts of the life of the 33-year-old mother, who is the only American known to have been killed fighting in Syria. They say some of Mansfield’s mysterious activity including a trip to the Middle East aroused the curiosity of the FBI, who contacted them a couple years ago to ask why Mansfield had traveled to Dubai for a few weeks.

“I was stunned, totally stunned, that she went over there and she got herself into what she got into and ended up away from us now,” said Monica Mansfield-Speelman, Mansfield’s aunt, of her niece’s trip to Syria, where more than 70,000 people have been killed during two years of civil war.

Family members said FBI agents visited them Thursday and informed them of Mansfield’s death. Simon Shaykhet, an FBI spokesman in Detroit, said he could confirm agents spoke to Mansfield’s family, but he declined further comment. A pro-Syrian government news agency said Mansfield and two others were fighters for a group opposed to Syria’s government and were killed in a confrontation in the northwestern city of Idlib. The report on the circumstances of the deaths could not immediately be confirmed.

Mansfield first became interested in the Middle East after a boyfriend introduced her to Islam several years ago, her relatives said. She continued with the religion after the relationship ended, going to services at a nearby mosque. She also started wearing a hijab and eventually did so around family despite their reservations.

She later married an Arab immigrant, got divorced and travelled to Dubai, telling her family at the time she wanted to learn more about Arab culture and the politics of the region, relatives said. Though family members asked questions, Mansfield, who has an 18-year-old daughter from a previous relationship, never told them the details of her marriage or trips overseas.

Mansfield-Speelman, who last saw her niece in August, said she and other family members did not approve of her niece’s conversion from Christianity to Islam and her short-lived marriage to a man they never met. The aunt said she doesn’t know the whereabouts of Mansfield’s ex-husband.

Her grandmother Carole Mansfield said she warned her granddaughter about taking the Dubai trip alone.

“I said, ‘Nikki, Nikki, Nikki, do you realize you’re looking a rattlesnake in the face?’ ” she said.