An unthinkable story made headlines in Canada this week: an Afghan-born father was found guilty of murdering his three teenage daughters, a fatal punishment for being too Westernized. If that's not alarming enough, two other killers were involved: the girls’ brother—and also their mother.

The crime has been characterized as an “honor killing”—the murder of a female for “shaming” her family by talking to boys, wearing Western clothing, or refusing an arranged marriage. The practice, which is rooted in the tribal traditions of South Asia and the Middle East, is horrific enough, but when girls die at a woman’s hand, it’s somehow even more tragic. And it is not a completely isolated incident. Across the world, in traditional Muslim culture and other traditional communities, older women routinely harass, punish, and sometimes even beat Muslim girls into submission. They are the aunts, mothers, and older women in the community who insist—right along with the men—that girls behave modestly. Girls often call these older women in their community their "aunties." Now they're earning a new name: "vigil-aunties."

It's not clear how the three teen girls in Canada were murdered, but the crime was made to look like an accidental drowning. The bodies were found in the family car, submerged in a canal. The perpetrators of the crime were their father, Mohammad Shafia; their mother, Tooba Mohammad Yahya; and the couple’s 21-year-old son, Hamed. The three girls—Zainab, 19; Sahar, 17; and Geeti, 13—had been dating boys, according to evidence presented in court. Zainab, the eldest, had a young Pakistani-Canadian boyfriend. Sahar, the second daughter, had condoms in her bedroom, which her parents had reportedly found.

The father claimed that his first wife, Rona Amir Mohammad, supported the girls in their Western ways. She was murdered too, bringing the death toll to four.

Mohammad Shafia showed no remorse for his actions. “Even if they hoist me up onto the gallows ... nothing is more dear to me than my honor,” he said in one recorded conversation.

Across the world in Pakistan, a “vigil-auntie” made news this week for going to a public park and chasing young women in burkas, or black face veils and gowns, who were out on dates with boys. Acting as a moral policewoman, she busted the couples on camera—on a Pakistani TV channel called Samaa. Thankfully, she was fired as a result, as her actions put the young people at risk. You can see one of the chase scenes if you go two minutes, 30 seconds into this tape.

The global headlines underscore a dynamic that hits close to home for me as an activist for women’s rights: women turning on women.

To be sure, there are open-minded aunties, including my mother and, yes, me, who wouldn't dare think of raising a hand for a supposed moral crime. But the reality is that, from our mosques to our extended families and communities, there are “vigil-aunties” making sure girls don’t "sin" by wearing sleeveless tops, jeans, or nail polish or by talking to boys—even in the West. These women have a weapon sometimes more lethal than physical torture. They inflict emotional torture that humiliates, shames, and chastises. They call girls “whores” and “sinners.” This can be more insidious and painful than the physical abuse.

These aunties see themselves as the “good girls,” and they assert their authority to keep the “bad girls” in check. Once, in my hometown of Morgantown, W.V., a “vigil-aunty” scolded me at the mosque for showing the small of my back when I bent over in prayer, my hoodie scooting up on my body. “You're checking out my butt at the mosque?” I asked her. Another time, a vigil-aunty invited me over for tea, only to lecture me on how I should repent for having had a baby without being married (the father never took responsibility). “You should spend the rest of your life, in a corner of the mosque, asking for forgiveness,” she told me. Meanwhile, her husband was secretly getting married to a second wife in Egypt.

At my mosque in Morgantown, my mother and I began to boldly sit among the men on the main floor a few years ago; the rest of the women stayed on the balcony above, as second-class citizens. The women shunned me for my actions. Another time, at the Islamic Center of Southern California in Los Angeles, I dared to take a space in the main prayer hall instead of a separate room designated for women. As I expected, a man ordered me to leave. I affirmed my right to the main hall. Then an older woman, Azmeralda Alfi, arrived, shrouded in a black covering. She was one of the senior members of the congregation, a mainstay who had emerged as a leader in the women’s circle. She stood over me—an authority in black, versus me in my flowing pink headscarf—demanding that I leave. “Think of me as your mother,” she told me. I couldn’t. My mother supported me. Although I had never met this woman before, I knew her well, because I had met so many who had played roles similar to the one she was playing that day. “She was one of the enforcers,” I told a friend.

Women being mean to women is clearly not something exclusive to Muslim society. Lewd images of American guards abusing Iraqi prisoners at Abu Ghraib stunned the world. In one photo, a 26-year-old woman named Sabrina Harman, a military-police officer from Lorton, Va., smiled as she stood beside an Iraqi female prisoner accused of being a prostitute. Behind the camera, a corporal, Charles Graner, took a picture of the two women. Military officials say Graner then forced the accused woman to expose her breasts and genitalia for another photo. Perhaps we will never know why Harman, a former worker at Papa John’s Pizza, stood by and watched.

In traditional Muslim society, women who perpetuate abuse upon women and girls have often grown up suffocating under the same rigidity and dogmatism they are now trying to enforce upon the next generation. In the global phenomenon in which the abused can often become the abuser, they repeat what they know. In the case of Noor Almaleki, the young Iraqi-American woman was killed by her father in Phoenix for being too Westernized; her mother supported the father in jailhouse conversations about the murder. At one point she told him, “You're not a criminal.” She and her husband hailed from a tribal community in Iraq. She repeated what she knew.

These traditions are deeply rooted, and deeply disturbing. In Canada, after the verdict was announced on the honor killing of the three girls, their mother, Tooba, said, “I am not a murderer, and I am a mother, a mother.”

It's time for us to challenge what is honorable and what is shameful in Muslim society with our moral compass guided by kindness and compassion, not violence, emotional or physical.