The murder comes as the world continues to track the progress of Malala Yousafzai, a 14-year-old Pakistani girl shot by Taliban Islamists after advocating for women's rights.
AFP reports that 20-year-old Mah Gul, who lived in Herat province in western Afghanistan, was killed after she had repeatedly rebuffed her mother-in-law's attempts to force her into prostitution.
Four people were arrested in connection to the killing, AFP adds, including the alleged beheader, the 18-year-old nephew of Gul's mother-in-law, Najibullah.
Najibullah, who has already confessed to the killing, said that Gul's mother-in-law had alerted him that the girl was a prostitute and that he killed the girl with a knife with the help of her mother-in-law.
The brutal torture and murder of Mah Gul by her husband's family is just "one more incident that highlights the violent atmosphere that women and girls face in Afghanistan and the region," said Suzanne Nossel, executive director of Amnesty International USA, according to CNN.
Earlier in October, a 30-year-old woman was tortured and killed in the same province, the Atlantic reported. The woman was discovered missing her nose, ears, and fingers, and doctors who treated her at Herat regional hospital confirmed she had been tortured before being killed. Investigation in ongoing in that case.
Gul's murder brings to 20 the number of women killed this year in Herat, the Atlantic adds reported. Family members were accused of involvement in most of the cases.
In a 2011 report on human trafficking in Afghanistan, the State Department wrote that some Afghan women and girls "are subjected to forced prostitution, forced marriages –- including through forced marriages in which husbands force their wives into prostitution, and where they are given by their families to settle debts or disputes."
In her full statement, Amnesty International's Nossel decried the ongoing violence in forceful terms.
“[Women] are raped, killed, forced into marriage in childhood, prevented from obtaining an education and denied their sexual and reproductive rights," Nossel said. "The enduring view that women and girls are disposable and not equal increases the chronic suffering of more than half the population."