Eight people including policemen, were given jail terms and four sentenced to death in connection with the killing.
The victim Farkhunda, was stoned to death, her body was run over by a car and set on fire at an Islamic shrine after being falsely accused of burning a copy of the Koran, BBC reported.
Keeper of the shrine Omran, who was the one to incite the mob, has also been acquitted by the court. The court decision taken in a secret hearing has attracted huge criticism from women's rights activists.
The victim argued with him before her death.
It showed that it was not only the Taliban but the whole Afghan system that oppressed women, said women activist, Wasjima Frogh.