One of the three Bethnal Green schoolgirls who left their homes to join Isis is believed to have been killed by an airstrike in Raqqa.
Khadiza Sultana, 17, is thought to have died after her home was destroyed by a bomb that was believed to have been dropped by a Russian plane.
She is believed to be the first British female killed in the so-called caliphate.
Tonight ITV News reveal that Sultana became disillusioned with life in the medieval terror state and was making plans to flee back to Britain.
The schoolgirl and two friends Amira Base and Shamima Begum left their families in east London during the Easter school holidays in 2015.
Base and Begum, who were both just 15 when they fled, and are believed to still be in Raqqa.
The trio became some of Britain’s most infamous Isis recruits and shocked the nation after leaving their A-Level courses and their families to marry fighters in Syria.
Sultana ‘s family were hoping to help to get her out of Raqqa and across the border into Turkey.
But it is believed Khadiza was killed before she could flee, after the property she was staying in was obliterated by the airstrike in May.
Sultana’s sister, Halima Khanom told ITV during the tense months when the desperate family hoped to secure her return to the UK: “Things have changed. The way she used to communicate with me.
“The way she used to talk about things has totally changed.
“Up until now. She’s scared of being there.”
Within the interview are recordings of phone calls between Halima and her younger sister before her death.
Sultana tells her sister “I don’t have a good feeling. I feel scared.
“You know the borders are closed right now, so how am I going to get out? I am not going to go through PKK [Kurdish forces inside Syria] territory to come out, I am never going to do that, ever.”
Later Halima asks: “How confident are you feeling in terms of getting out?”
Khadiza: “Zero….. Where is Mum? I want to speak to her.”
Speaking straight after the phone call Halima said: “She sounds very terrified.
“She did get very emotional there as well. It feels…I feel really helpless. What can I do? It’s really hard. I don’t think she’s ever made a choice by herself.
“That was the first one and a very big one. I just look forward to the next call and that’s what keeps me going.”
It is believed the teenager was inside a residential building when it was struck by the airstrike.
Halima Khanom, Sultana’s sister: “We were expecting this in a way. But at least we know she is in a better place.
“We do not wish her name to come up in the headlines again. She is gone and we would like to respect her wishes.”
The families of all three Bethnal Green schoolgirls made headlines in February 2015 after making a series of desperate public appeals for information on the missing teenagers.
It is believed that all three wed fellow foreigners who were fighting for the Islamic State.
Khadiza’s husband was an American national of Somali origin who died late last year.
All three families were represented at the time of the schoolgirls’ disappearance by lawyer Tasnime Akunjee, who said: “Leaving Isis is like trying to escape from Alcatraz, with a shoot to kill order added in.
“It’s devastating for the family that it ended like this.
“Perhaps the only benefit out of this is as a tombstone and a testimony for others of the risks of actually going to a warzone, to dissuade people from ever making that choice.”
The Bethnal Green schoolgirls were among more than 800 Britons believed to have left the UK to join Isis or other militant groups in Syria and Iraq.
It is thought that at least 250 have since returned.
Metropolitan Police Commissioner Sir Bernard Hogan Howe told MPs last year the Bethnal Green trio would be unlikely to be prosecuted if they returned to Britain unless there was evidence they had committed any specific crimes while with Isis.
The fate of the other two Bethnal Green schoolgirls is still unknow, but it is is believed the pair continue to live in Raqqa.
There is no suggestion that either Abase or Begum have given any hint of disillusionment with IS.
Watch Rohit Kachroo’s report on ITV Evening News at 6.30pm and ITV News at Ten.