Kadiza Sultana, one of three schoolgirls who left their homes in Bethnal Green in February 2015 to join the so-called Islamic State (IS) is believed to have been killed by an airstrike in Raqqa.
Kadiza had travelled with her friends Amira Base and Shamima Begum, who were both just 15 when they fled, and are believed to still be in Raqqa.
Before her assumed death, the 17-year-old had become disillusioned with life in Syria and had been discussing plans with her family to flee the country and return to the UK.
"I don't have a good feeling"
In one phone call with her sister Halima Khanom filmed by journalist Joshua Baker in December 2015, Kadiza revealed her fears about whether she would be able to return safely.
"I don't have a good feeling, I feel scared," she said.
"You know if something goes wrong that's it...I'll never be able (to come home)," she added.
She also expressed concerns about the potential route she would take out of the country.
"I'm not going through PKK territory to come out"
"You know the borders are closed right now, so how I'm going to get out? I'm not going through PKK (militant Kurdistan Workers Party) territory to come out, I'm never going to do that ever.
The plan discussed would have involved Kadiza taking a cab to a safe house, but when asked by her sister how confident she was feeling about this aspect of the plan, the teenager replied "zero".
"I want to speak to mum"
Kadiza is then heard asked to speak to her mother: "Where's mum? I want to speak to mum.
After the phone call had ended, a visibly concerned Halima said: "She sounded very terrified. And she did get very emotional there as well."
"I really feel helpless...I can just sit here, what can I do. It's really hard".
Following reports of Kadiza's death, her family confirmed details in a statement to ITV News.
Halima said: "We were expecting this in a way. But at least we know she is in a better place.
"She is gone and we would like to respect her wishes," she added.