She was raised in a well-heeled Glasgow suburb, attended an exclusive Scottish girls’ school that could have come from the pages of Muriel Spark’s novel The Prime of Miss Jean Brodie, and is described by bewildered family and friends as a once “sweet, intelligent and peaceful” girl. But yesterday the parents of 20-year-old Aqsa Mahmood revealed she is one of the female jihadists behind the online campaign reported on by The Daily Beast to recruit Western girls.

Western terrorist experts think the operation is a drive endorsed by the self-proclaimed Islamic State, widely known as ISIS or ISIL, to lure Western women to the marriage beds of the caliphate’s holy warriors, and it relies on those already enlisted to promote jihad.

Potential recruits are told their main role in the Islamic revolution will be through matrimony and childbearing, not martyrdom. And Mahmood, using the Twitter handle Umm Layth, has been highly active on Twitter and on her blog trying to persuade would-be “sisters” in Europe and the United States to travel to the Middle East to help ISIS establish its extremist vision of a militant Islamic utopia.

Mahmood ran off last November, according to her parents, who reported her as missing to police, and she is understood to have married a jihadist fighter soon after arriving in the Syrian city of Aleppo.

Much of Mahmood’s output has eschewed the gore and the barbaric images frequently included in the general fare of jihadist online posts, focusing instead on the private sphere of being a jihadist wife, but the girl described as peace-loving has also been urging Islamic militants in the West to follow the example of the Boston Marathon bombers, Chechen brothers Dzhokhar and Tamerlan Tsarnaev, and to copy the brutality of the murderers of British soldier Lee Rigby, who was hacked to death in broad daylight on the streets of London.

“Follow the examples of your brothers from Woolwich, Texas and Boston,” she tweeted. “If you cannot make it to the battlefield, then bring the battlefield to yourself.” Her online diary incites others to leave family behind as she left her comfortable middle-class life, promising, “Once you arrive in the land of Jihad [it] is your family.” In one of many tweets to her 2,000 followers, she says, “Gain true honor by living under the law of Shariah.”

In a statement read by their lawyer, her clearly distraught Pakistani-born parents warned yesterday: “If our daughter who had every chance and freedom in life could become a bedroom radical, then it is possible for it to happen to any family.” Her father built a successful business and the family lives in an $800,000 sandstone house in a posh Glasgow suburb. Term fees at her girls’ school, Craigholme, are $6,000.

School friends say that before she started to pair a hijab with her school kilt, Mahmood was very much a Western girl who enjoyed makeup and clothes and discussed boys with her friends. She was a fan of Coldplay and a Harry Potter reader until an Australian Muslim preacher denounced J.K. Rowling’s works for glorifying and promoting paganism. At 15 a process of radicalization appears to have started—apparently hidden from her parents and most of her friends—and she spent increasing amounts of time locked away in her bedroom and interacting on radical Muslim chat forums.

On a Tumblr account she started in January 2013, 10 months before setting off for the Middle East, she posted pictures of jihadist fighters in Syria. She told some friends, according to the Scottish Daily Record, that she wanted to go to Syria to help people there fight President Bashar al-Assad. Although she was a studious girl, her final exams were disappointing and she failed to gain a university place on her first try. She started studying diagnostic radiotherapy at a second-tier Scottish university before abandoning it for life as a jihad wife in Syria.

Mahmood is one of at least 50 British women and girls who are thought by security experts to have joined ISIS in Syria, although some argue the number may be higher. Her parents, through their lawyer, insist that as a middle-class woman and at one time a successful student she is not a “stereotypical” case. But many male and female Western ISIS and al Qaeda recruits come from middle-income backgrounds and are often fairly well educated—the 9/11 hijackers were.

What is distinguishing ISIS from its rival al Qaeda is the increased role the group is giving women as online recruiters and as enforcers of Sharia religious law in the swath of territory ISIS now controls in eastern Syria and western Iraq. The fear is that the Western women may take on an even more active role as suicide bombers. Olivier Guitta, a terrorist adviser to the British government, says ISIS may be priming female recruits for attacks “in the homeland.” U.S. officials also say they are worried that it is not only Western male recruits who might mount attacks on their return.

In 2005 Iraq was rocked by a series of suicide bombings carried out by women—the first time any al Qaeda branch had used female jihadists as bombers. The bombings, which amounted to a breaking of an al Qaeda taboo, were the brainchild of Jordanian-born terrorist Abu Musab al-Zarqawi, the mentor of Abu Bakr al-Baghdadi, the leader of ISIS.

One of the women bombers was a Western recruit—38-year-old Belgian Muriel Degauque, from the rust-belt city of Charleroi near the French border. On November 9, 2005, she blew herself up attacking an Iraqi police post in the town of Baqubah.

How many more “bedroom radicals” like Aqsa may be dreaming of such exploits is, at this point, impossible to say.