Eighteen months after British schoolgirl Kadiza Sultana ran away from home to join the Islamic State militant group, her family lawyer says they've received word she has died in Syria.

According to ITV, the family received a call "to say Kadiza had been killed in an airstrike." Family lawyer Tasnime Akunjee told the BBC that they are "very obviously devastated," and added that they had not been able to independently confirm the report.

Kadiza Sultana was 16 years old when she fled the U.K. and took a flight to Istanbul with two friends from school. Authorities said the three then crossed the border into Syria. The news made headlines in the U.K., as NPR's Ari Shapiro reported last year.

"They're described as good students, modern, well-integrated, well-adjusted kids," Ari said. "The parents say they never heard their daughters express interest in events in the Middle East."

According to Kadiza's family, she had made contact with them and expressed second thoughts about remaining in Syria with the militant group, ITV reported. The family had traveled to Turkey and were trying to craft a plan to bring her out of Islamic State-held territory.

Kadiza told her sister Halima that the "man she married was killed, and she wants to come back," according to ITV.

"I don't have a good feeling. I feel scared," she said in a phone call recorded on video. "You know if something goes wrong, that's it. I'll never be able (to come home)."

"The only thing I would say to you, is just trust us," Halima told her sister. She replied: "All the borders are closed right now, so how am I going to get out?"

Akunjee, the family lawyer, said on ITV that he hopes others will see this story as "a testament to others that these are the risks that are actually involved in going to a war zone. To dissuade people from ever making that choice, really."

The situation of Kadiza's two travel companions is currently unknown. But as ITV reported, "there is no suggestion that either Amira Abase or Shamima Begum have given any hint of disillusionment with IS. It is believed the pair continue to live in Raqqa."

More than 800 people from the U.K. have gone to fight in Syria or Iraq, according to The Associated Press. But this case struck a chord, as Ari reported:

"The women who've gone over have rarely been as young as these girls. And these teenagers seemed well integrated into society, which makes this a really frightening scenario for parents who may feel that even if they try to do everything right, their kids could still be at risk."

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