But police quickly said they were looking at Mangal’s broad-daylight killing as the result of a family dispute, saying her ex-husband had “probably” played a role.
The brazen attack last weekend sparked global outrage over the plight of Afghan women, who still suffer rampant levels of physical and mental abuse, sexual violence and discrimination.
Authorities say Mangal’s death came amid the type of suffocating marital dispute that is common for many women in Afghanistan, a country where domestic abuse can seem like the norm and women are often seen as little more than household chattel.
Her killing has garnered broad condemnation — including from the US and from Canadian Prime Minister Justin Trudeau.
In Kabul, the attorney general’s office said Mangal had filed a complaint saying she was mistreated by her husband, whom she had felt pressured into marrying after a 10-year engagement.
“She was not happy about her relationship from the very beginning,” Jamshid Rasuli, a spokesman for the attorney general’s office, told AFP.
Rasuli said Mangal’s husband had threatened to kill her, and she was eventually granted a divorce — no easy feat in a strictly Islamic country whose male-dominated courts favour men.
The ex-husband remains at large and is being sought by police, who have vowed a thorough investigation.
But Mangal’s father, Talib Jan Mangal, said he thought police were not doing enough.
“If he is not arrested, he can threaten our lives too,” he told AFP.
Mangal, who reportedly was 27, posted a message on social media days before she died saying she had received a death threat — though she did say who it was from.
She was relatively well known in Kabul thanks to her experience as a broadcast journalist and her work as an activist.
Mangal was also known in political circles, having quit journalism three years ago to work as an adviser for the Afghan parliament’s religious and cultural affairs committee.
Gender equality in Afghanistan has improved somewhat since a US-led coalition toppled the hardline Taliban regime in 2001.
The insurgents were notorious for denying women and girls any education, forcing women to wear burqas and for stoning them to death on trumped-up charges.
Women today — particularly in urban areas — hold professional jobs, as well as about a quarter of the seats in parliament.
But major challenges remain, with forced marriages and child marriages still common.
Samira Hamidi, a South Asia campaigner for Amnesty International, said Afghan women remain vulnerable, and authorities are ill-equipped to investigate crimes.
“Unfortunately Mena’s killing is not the first one,” Hamidi told AFP.
“There have been many women intimidated, harassed, abducted, threatened and eventually killed — but there has not been a mechanism to investigate the crime and bring perpetrators to justice.”
In 2015, a woman known as Farkhunda was beaten to death in Kabul after being falsely accused of blasphemy, a case that became a symbol of the endemic violence that women still face.
Shagufa Noorzai, a female member of parliament, posted images of Afghan abuse cases on Twitter including portraits of Mangal, Farkhunda, a woman whose nose had been cut off by her husband, and a young girl who’d been kidnapped and murdered.
“All these crimes took place mainly during the day” in Kabul, she wrote on Twitter, adding the hashtag #StopKillingWomen.
Mary Akrami, director of the Afghan Women Network, told AFP violence towards women remains common partly due to a “culture of impunity”.
“Lawlessness, a lack of proper punishment and corruption in the judiciary system have given men a sense of impunity,” she said.
Akrami also pointed to women’s continued lack of access to information about their rights.
After Mangal’s death, Akrami and others started a WhatsApp conversation with over 100 female participants.
“None of the women had any ideas on how to deal with such a situation. They all believed the men were too powerful to deal with,” Akrami said.
The plight of Afghan women has received renewed focus in recent months, as many fret that rights will be lost if the US cuts a peace deal with the Taliban.
Such an outcome seems far off, and it is unclear what kind of power the Taliban could end up wielding across Afghanistan.
But a deadly Taliban attack on a US-funded aid group last week does not bode well.
The insurgents said they targeted the organisation, killing nine people in the process, because it promoted the “inter-mixing” of men and women.