When the three Dawood sisters abandoned their husbands in Britain and made their way to join the self-styled Islamic State in Syria, the story made headlines across the UK.
Sociologists, politicians and pundits scrambled to explain how grown-up mothers with nine children ranging from three to fifteen could take such a step.
After all, they were leaving one of the safest, most liberal places in the world for the most intolerant and dangerous land anywhere.
Repeatedly, the three husbands - all of Pakistani origin - were shown on TV, tearfully begging their spouses to return to them. Columnists and editorial writers have devoted acres of newsprint in trying to explain the phenomenon of hundreds of Britons finding their way to Syria to join the so-called Islamic State.
The same question is being asked across Europe and the United States as their citizens, too, fly to Turkey and make the land journey across to Syria.
However, it is only recently that Turkey has been trying to stop these wannabe jihadis: until a few months ago, they were allowed free access.
And there are still signs of Turkish support for extremist groups fighting in Syria.
Questions about Muslims who are joining IS take on greater urgency against the backdrop of heightened terrorist threats in Europe.
The fear is that many of those European nationals now in Syria will return and pose a grave danger to the security of their home countries.
Trained and highly motivated, they could indeed unleash a wave of terror.
Several have been arrested on their return to the UK, and will be tried under tough anti-terrorism legislation.
Rod Liddle, the satirical right-wing columnist, recently wrote in The Spectator about the 15-year-old Amira Abase, who, together with two friends, fled from London to Syria last February.
Her father, Hussen Abase, an Ethiopian immigrant, blamed the police for not stopping his daughter at Gatwick airport.
It later emerged that he had attended rallies organised by the extremist group, Al Muhajiroun, and was photographed there burning an American flag.
Apparently, he had taken young Amira to at least two such rallies. Liddle writes:
"Hussen is an Ethiopian and of course - of course - unemployed. He came to this country, he said, for democracy and freedom.
And also, presumably, so that he and his appalling family can be heavily subsidised by the taxpayer while they scream for the destruction of the civilisation which has treated them with such ludicrous, arguably insane, generosity.
I came here for the right to demand your utter and complete destruction while being extravagantly remunerated for so doing. Any problem in that?"
In another column, Liddle argued that anybody choosing to fight for IS should not be allowed to return to the UK.
This view is being increasingly voiced privately even by liberal Brits. And the recent attack on foreign tourists at a beach resort in Tunisia that killed nearly forty holidaymakers has only increased the sense of fear and anger.
The mystery of the attraction IS has for middle-class British Muslims continues to be the subject of much speculation.
Among the "pull factors" is the image of young men in black uniforms with Kalashnikovs, fighting the West and its Arab allies.
Videos on social media obviously resonate with immature young men.
And the promise of numerous 'wives' must also attract shy, inhibited teenagers who are unsuccessful at finding girlfriends in Europe.
But what's in it for girls and young women? According to one journalist who has contacted several 'brides of IS' on social media sites, the attraction of leaving the constraints imposed by strict fathers or husbands is strong.
For instance, all three Dawood sisters, while born and brought up in the UK, had to endure arranged (or forced) marriages to Pakistani men.
IS promises women easier divorce if they are mistreated by their husbands than most Muslim societies do.
In the UK, women's freedoms are similarly curtailed by conservative Muslims who are cut off from mainstream Britain.
And for both men and women, IS holds out a promise of a fair and equal society.
Of course, leaving the brutal 'state' is another matter.
According to reports, some 400 disillusioned European volunteers have been executed for trying to return to their home countries.
And yet, despite the constant horror stories emerging from Syria and Iraq, more and more young Muslims from the West continue to make the journey.
Recently, David Cameron demanded that Muslims in Britain should do more to dissuade young men and women from undertaking the journey to Syria, partly blaming the community for this radicalisation.
Several liberal commentators attacked the prime minister for his speech.
While clearly the problem lies with European Muslims, the reality is that young believers - usually ignorant of Islam and Islamic history - are indoctrinated online as well as by their peers.
Their parents and the local cleric have little influence over them. This is an extreme form of youthful rebellion whose equivalent is the way teenagers join violent gangs that fight over turf in many urban areas in the West.
For the last few years, Britain has been running a campaign called 'Prevent' aimed at guiding young Muslims away from extremism. Millions of pounds have been spent on this effort, and yet there is little evidence to suggest that the programme has succeeded to any degree.
But given the increased threat level, the fight for online privacy has received a setback.
It is hard to argue, as liberals do, that the GCHQ - the British equivalent of the American National Security Agency - should be restrained in its massive collection of electronic data.
Increasingly, the atrocities committed by IS and other Islamist groups in the Middle East and elsewhere will erode the position of Muslim migrants in the West.