KABUL, Afghanistan - Afghan women's rights activists dressed head-to-toe in black broke with tradition Sunday to carry the coffin of a woman who was beaten to death by a mob in the capital Kabul over allegations she had burned a Quran.

The mob of men beat Farkhunda, 27, before throwing her body off a roof, running over it with a car, setting it on fire, and throwing it into a river near a well-known mosque. The attack was apparently sparked by allegations that Farkhunda, who like many Afghans has just one name, had set fire to a Quran. But Afghanistan's most senior detective said no evidence had been found to support those claims.

Video of the assault taken with cellphones has circulated widely since the attack Thursday. The killing has shocked many Afghans and led to renewed calls for justice and reform.

"We want justice for Farkhunda, we want justice for Afghan women. All these injustices happening to Afghan women are unacceptable," said a women's rights activist who goes by the name Dr. Alima. "In which religion or faith is it acceptable to burn a person to death? Today is a day of national mourning and we will not keep quiet."

President Ashraf Ghani, now in Washington on his first state visit to the United States since taking office in September, condemned the killing as a "heinous attack" and ordered an investigation.

Following allegations that police stood by and did nothing to stop the killing, Ghani told reporters before leaving for the U.S. that the incident revealed "a fundamental issue" - that security forces are too focused on the fight against the Taliban insurgency to concentrate on community policing.

Many rights activists, however, said the killing cut to the core of how women are treated as second-class citizens in Afghan society. Despite constitutional guarantees of equal rights and advances in access to health and education, for many women little has changed since the 2001 U.S.-led invasion ended the Taliban's rule.

Hundreds gathered at a graveyard Sunday in the middle-class suburb near Farkhunda's home. With the permission of her father, the women in black carried her coffin from an ambulance to an open-air prayer ground, and then to her grave, rituals that are usually attended only by men.

"She is a sister to you all, and it is your duty to bury her," Farkhunda's brother Najibullah told the crowd. Several politicians, officials, and others also addressed the funeral, which was broadcast live.