One of three schoolgirls who left east London last year to join so-called Islamic State (IS) is believed to have been killed in a Russian air strike in Syria, her family solicitor has said.
Kadiza Sultana was 16 when she left Bethnal Green along with two friends.
Her family's lawyer, Tasnime Akunjee, told BBC Newsnight they heard a report of her death in Raqqa a few weeks ago.
But he said they had not been able to independently confirm it because of the nature of information from Syria.
Mr Akunjee said the teenager had grown disillusioned and wanted to leave IS and return to the UK - but had decided not to risk being captured and facing a "brutal" punishment from the terror group.
He told the programme the family were "devastated" and that it was a "great loss to us all".
Kadiza Sultana and schoolfriends Shamima Begum and Amira Abase, both 15 at the time, flew from Gatwick to Turkey on 17 February 2015 after telling their parents they were going out for the day.
The Bethnal Green Academy pupils later entered Syria and were thought to be living in Raqqa, a stronghold for the so-called Islamic State.
They had been studying for their GCSEs at the school in Tower Hamlets, east London - where they have been described as "straight-A students".
Mr Akunjee said Kadiza had expressed a desire to return.
He said: "The problem with that was the risk factors around leaving are quite terminal also, in that if ISIS [IS] were able to detect and capture you then their punishment is quite brutal for trying to leave.
"In the week where she was thinking of these issues a young Austrian girl had been caught trying to leave ISIS territory and was by all reports beaten to death publicly, so - given that that was circulated in the region as well as outside - I think Kadiza took that as a bad omen and decided not to take the risk."
Mr Akunjee added: "I think she found out pretty quickly that the propaganda doesn't match up with the reality."
Recordings of phone calls between Kadiza and her sister Halima, who is in the UK, were filmed by a freelance journalist for ITV.
In them, Kadiza said the man she had married had been killed, and that she wanted to return to the UK. She also said she "felt scared".
She added: "You know if something goes wrong, that's it. You know the borders are closed right now, so how am I going to get out?"
A fourth girl from the school is believed to have travelled to Syria in December 2014.
Kadiza's family issued a statement shortly after she went missing.
In it they said: "In your absence, we, as a family, are feeling completely distressed and cannot make sense of why you left home. Due to the speculation that you may be travelling towards Syria, we are extremely worried about your safety.
"We would like to emphasise that we are not angry with you and you have not done anything wrong. We just want you all to return home, safe and sound."
Sara Khan, co-founder of the counter-extremism organisation Inspire, told BBC Radio 4's Today programme that she saw Kadiza as a victim, "because she's not an adult".
Young girls who are exposed to radicalisation "lack critical thinking skills", which "is what makes them vulnerable to Islamist extremist propaganda in particular", she said.
She added that girls being exposed to extremist material were "not receiving counter messages".
Rushanara Ali, the Labour MP for Bethnal Green and Bow, also told Today that the government's Prevent strategy to stop radicalisation was not working, with some of it being "quite misguided".
"What the government needs to do is do a proper assessment of what's working and what's not and they need to listen to the Muslim community...
"But that requires partnership between communities."
Last year, a solicitor for the families said two of the girls had got married, without identifying which ones.
The Bethnal Green schoolgirls were among more than 800 Britons who are believed to have left the UK to join IS or other militant groups in Syria and Iraq,
In February 2015 the principal of Bethnal Green Academy, Mark Keary, said there was no evidence that the girls were radicalised at school, adding that pupils could not access Twitter or Facebook on its computers.
It later emerged that, before leaving the UK, Shamima Begum had sent a Twitter message to Aqsa Mahmood, who left Glasgow for Syria in 2013 to marry an Islamic State fighter.
A spokeswoman for the Foreign Office said: "The UK has advised for some time against all travel to Syria. As all UK consular services there are suspended, it is extremely difficult to confirm the status and whereabouts of British nationals in Syria.
"Anyone who does travel to these areas, for whatever reason, is putting themselves in considerable danger."