Patrolling the streets of Raqqa, in Syria, a group with dozens of young women arrest and punish all other women who don't abide by the strict rules of the now-governing Islamic State. These are the women of the IS Police Al-Khanssaa Brigade, who roam the city armed with AK-47 looking for indecency crimes, such as showing an ankle, report on men who misbehave and manage brothels filled with sex slaves. The group's methods are so brutal and extreme that some of its members have come to regret their actions and tried to escape; that's exactly what two women did, successfully, earlier this year.

Hiding in southern Turkey, where they are living illegally, they are now telling their story.

"What upset me most was lashing old women when they weren't wearing the proper clothes," one of the women said, completely covered by a niqab except for the eyes, in an interview with Sky News. The standard punishment is 40 lashes for women who fail to wear the abaya (the long Islamic dresses) or choose to wear a form-fitting one; high heels or coloured shoes are forbidden, they cannot show ankles, wrists or face. If women try to escape upon being arrested by the female police brigade, then the punishment is 60 lashes. And these are applied in maximum strength, medieval style. The agents of the brigade earn between £100 and £150 per month and receive training in the use of weapons.

Doaa and Umm, fake names the two women use in the interview, are extremely young - 20-years-old - as are all of the female agents, who are recruited between ages 18 to 25. They are commanded by Umm Hamza, a six-foot-tall woman dubbed "The Slaughterer," who instiles fear within and outside the group. Now for the chilling part: most of the members of the terrifying brigade are educated westerners.

Worse: a lot of them are British.

It's the case of Aqsa Mahmood, from Glasgow, and Khadijah Dare, from Lewisham, who started documenting their operations in the brigade last year, both with terrible details - including pictures holding decapitated heads and tweets describing the Yazidi sex slaves. Sexual violence is a common trait of IS fighters and while most of it is committed against slaves, there are numerous reports of assaults by fighters on their wives.

The prospect of being one such victim was the reason why a Syrian schoolteacher turned Al-Khanssaa Brigade agent fled the force late last year, also to Turkey, while her family remains in Syria.

Her account of the atrocities she witnessed was given to CNN, with a brief mention of the feared Umm Hamza, whom she dreaded. Sensing her fear, another commander told her: "We are harsh with the infidels, but merciful among ourselves."

Now, that might be just a matter of interpretation. The Al-Khanssaa Brigade released a document in January explaining the role of women in the Islamic State. Written in Arabic, it was translated to English by the Quilliam Foundation and provides a much-needed context on why these women are so crude against other women, and act with such violence against anyone that they perceive to go against the "true" implementation of Islam.

Per their words, "It is always preferable for a woman to remain hidden and veiled, to maintain society from behind this veil." They denounce the falsehood of equal rights between men and women, forced by the West, and portray Raqqa in Syria and Mosul in Iraq, the two strongholds of IS, as having returned to peace and justice for women. "It is considered legitimate for a girl to be married at the age of nine," they add.

The Sky News piece is just the tip of the iceberg and doesn't even begin to cover the savagery committed by the all-female brigade, while also making us wonder why two escaped officers would consent to a televised interview when they fear the Islamic State will come for them in Turkey.

But these are the stories western media needs to tell systematically, as they make for a more accurate portrait of what awaits european women (more than 600 have joined ISIS) who romanticise life as a jihadist wive.