An outraged Afghan President Ahmed Karzai has ordered immediate arrest of the Taliban militants who carried out the merciless act.
The crime the woman was accused of: adultery and that too because of a possible Taliban love triangle.
Karzai described those involved in the shooting death as "cowards," saying "such crimes are unforgivable both in Islam and under our country's laws," the statement from his press office said.
Shock and outrage have mounted since the amateur video surfaced showing the woman sitting on the ground while a man standing a few feet away shoots her with an AK47 nine times before a cheering mob.
The video, which has begun circulating in Kabul, recalls the Taliban's five-year reign in Afghanistan, when public executions were advertised on the radio and people accused of crimes were shot in front of crowds that packed the capital's stadium, The New York Times said.
The execution took place in the Shinwari district of Parwan Province, in central Afghanistan, less than a two-hour drive from Kabul. It occurred on or around June 23, said Col Masjidi, a senior provincial police official.
The horrific video shows a crowd of men gather to watch a gunman shoot her in the head and back.
The unidentified shooter, who is seen wearing an orange beret, swiftly executes her - but continues to shoot her dead body while walking towards it. In all, nine shots were fired.
Afghan officials believe the woman was executed because two Taliban commanders had a dispute over her, according to the governor of the province where the killing took place.
Both apparently had some kind of relationship with the woman, Parwan province Governor Abdul Basir Salangi said.
To save face, they accused her of adultery, Salangi told CNN. Then they "faked a court to decide about the fate of this woman and in one hour, they executed the woman," he added.
However, there are different versions to the reason behind the killing.
Colonel Masjidi said the woman's real husband was a member of a village militia that had slain a local Taliban leader. The woman was executed in revenge on trumped up charges of adultery, he said.
Roshna Khalid, a spokeswoman for the provincial government, said the woman was killed for having multiple affairs with Taliban fighters. Khalid said the woman's name was Najiba, and that she was in her 20s and did not have children, the NYT reported.
A third official, Qari Abdul Rahman Ahmadi, a member of the provincial council, said the woman had run off with a Taliban commander, who in turn was accused of passing information to government forces.
He was shot in a nearby village before Najiba was executed by her husband, Ahmadi said.
The American Embassy in Kabul and the NATO-led coalition condemned the execution. UK too has condemned the act.