Samra Kesinovic, 17, and her friend Sabina Selimovic became ‘poster girls’ for ISIS after they arrived in Syria in April 2014.
A number of Austrian newspapers have reported that Samra has been beaten to death for attempting to leave Raqqa, although official government sources are refusing to comment on individual cases.
According to The Local, one newspaper quotes a Tunisian woman who lived with Samra and Sabina in Raqqa.
The Tunisian woman, who was not named in the report, said she was able to escape from ISIS.
Earlier this year, a United Nations official says one of the two Austrian girls who fled their middle class homes in Vienna earlier this year to fight in Syria has definitely died in the conflict.
They first went to the Turkish capital Ankara by plane, and then on into the southern Turkish region of Adana. After that, their tracks were lost.
But they appeared on social networking sites branding Kalashnikov rifles and surrounded by armed men – photos which Austrian police said acted as recruitment posters for young girls.
David Scharia, a senior Israeli expert of the United Nations Security Council’s Counter-Terrorism Committee (CTED) said: ‘We received information just recently about two 15-year-old girls, of Bosnian origin, who left Austria, where they had been living in recent years; and everyone, the families and the intelligence services of the two countries, is looking for them.
He added: ‘Both were recruited by Islamic State. One was killed in the fighting in Syria, the other has disappeared.’
His confirmation comes three months after the Austrian government said it had informed both sets of parents of the girls that one of them might have been killed.
Read more: DailyMail.co.uk