Prior to her death, she was forced to be a sex slave for the terror group, according to a Tunisian former extremist who lived with the two girls in the terror group's de facto capital.
The Tunisian woman said the two Austrian teenagers lived together in the same house and were viewed as a "sexual present for new fighters".
Earlier this year, a United Nations official revealed a girl "of Bosnian origin from Austria" - believed to be Miss Selimovic - died in fighting in Syria.
The two girls were children of Bosnian refugees who fled to Austria in the 90s to escape the war in their homeland.
They reportedly left a note for their families, which read: "Don't look for us. We will serve Allah and we will die for him."
In April 2014, the two travelled via Turkey to Syria where it is thought they both married jihadists.
An Islamic preacher from Bosnia living in Vienna, Mirsad O., known by the Islamic name of "Ebu Tejma", was allegedly responsible for the radicalisation of the two young girls. He has denied the claims.
He was arrested for his role in an alleged terrorist funding network based in Austria in November.
Shortly after arriving in Syria, Sabina, speaking through SMS messages to a French magazine, insisted she was enjoying life in the war-torn region where she felt free to practise her religion.
She said her husband was a soldier and added: "Here I can really be free. I can practice my religion. I couldn't do that in Vienna."
As many as 130 people from Austria are now believed to be fighting as jihadists abroad.
Experts say at least half of them originally come from the Caucasus region of Russia and were granted asylum in Austria after the bloody Chechen war.
Austrian Interior Ministry spokesman Alexander Marakovits said the lure of Isis for young people was an increasing problem for the authorities.
He said: "If we can catch them before they leave we have the chance to work with their parents and other institutions to bring the youngsters out of the sphere of influence that prompted them to act in this way in the first place.
"Once they have left the country, even if they then changed their minds, it is then almost impossible to get them back."
Roughly half a million Muslims live in Austria today, around 6 per cent of the population. Many of them have Turkish or Bosnian roots.
- Daily Mail
