After the murder of Hakimi, the group is then alleged to have posted pictures of her decapitating head on social media, possibly as a brutal warning to others.
Conflicting reports have emerged about the death of the young girl.
A death certificate that emerged showed she had possibly died a week before the Taliban took control following the retreat by the US and its allies from the country.
Other claims state that the young athlete took her own life.
A leaked photo of her body showed wounds to her neck, but it wasn't clear if a blade or a ligature point had caused this.
However, the Afghanistan based Payk Investigative Journalism Centre said that its sources had confirmed that Mahjabin had been "beheaded by the Taliban in Kabul".
In an interview with the Persian Independent, one of Hakimi's coaches - speaking under a pseudonym - said that she was killed in early October but that it had been kept a secret as her family had been threatened not to talk about it.
Dozens of female athletes have fled Afghanistan in fear of their lives since the Taliban swept back into power in August as the preexisting Afghan Government collapsed.
The Taliban has banned all sports for females since taking power, and have yet to allow girls to return to school for an education.
Only two of the women's youth volleyball team's players managed to escape Afghanistan, it has been reported.
"All the players of the volleyball team and the rest of the women athletes are in a bad situation and in despair and fear," the coach said, according to the Persian Independent.
"Everyone has been forced to flee and live in unknown places."
Hakimi played for Kabul Municipality Volleyball Club before the Taliban seized power.
Afghanistan's Chef de Mission at the Tokyo 2020 Paralympics, Arian Sadiqi, fears for the lives of 12 Para athletes who are still stuck in the country and is worried that those who did not escape when the Taliban seized power have been forgotten about.
"If these girls don’t get help soon, they may fall into the hands of the Taliban and may get killed," Sadiqi said, according to Insidethegames.
Athletes Noorja Najafi, Rahela Haidari, Nargis Masomi and Benafsha Najafi have all called on European countries to help evacuate them from Afghanistan.
"The right to education has been taken away from us," said Najafi in a video.
"We cannot go to university safely or study safely because we are disabled," Najafi continues in the video.
"Without wearing a hijab, we cannot walk or go out.
"We are very worried that our lives are in danger."
The women's national volleyball team has petitioned for foreign organisations to help get them out of the country, but have so far been unsuccessful.
"Our players who were living in the provinces had to leave and live in other places," Zahra Fayazi, a coach for Afghanistan, told the BBC in September.
"They even burned their sports equipment to save themselves and their families.
"They didn't want them to keep anything related to sport.
"They are scared.
"Many of our players who are from provinces were threatened many times by their relatives who are Taliban and Taliban followers.
"The Taliban asked our players' families to not allow their girls to do sport, otherwise they will be faced with unexpected violence."
"I
don’t even have words to describe this message I received today on
Instagram. I have now blocked the profile. I want to know if it’s even
possible to report this hateful racist message to any authorities ? It’s
a secret profile so it seems like there is nothing else to do than to
report it to Instagram. I have a lot to say to the person behind this
profile but let me just share the message for the world to see this
cowards stupidity !!" Anja wrote. 
