The so-called Islamic State is recruiting Western kids with techniques pedophiles use to groom underage sexual prey. The jihadists are pushing harder than ever, and alarm is growing in Europe, especially Britain, where last weekend police announced they had arrested a 14-year-old boy and 16-year-old girl on terror charges.

The two teens were picked up in northern England towns near by Manchester. It remains unclear whether they were planning to follow in the footsteps of at least 600 Britons and join the self-styled Islamic State in Syria or were scheming to carry out a terror attack in Britain. They were held on the catchall charge of “preparing acts of terrorism.”

The arrest of these minors—police have so far not named them—prompted a senior Muslim lawyer to warn Monday that hundreds of British teenagers are in danger of being radicalized because they see the terrorists as “pop idols.” Nazir Afzal, a former top prosecutor, told Britain’s Guardian newspaper that recent departures to Syria show “many more children” are vulnerable to “jihadimania” than was previously thought.

“The boys want to be like them and the girls want to be with them,” he said. “That’s what they used to say about the Beatles and more recently One Direction and Justin Bieber. The propaganda the terrorists put out is akin to marketing, and too many of our teenagers are falling for the image.”

He added: “The extremists treat them in a similar way to sexual groomers—they manipulate them, distance them from their friends and families, and then take them.”

Mia Bloom, a security studies professor at the University of Massachusetts at Lowell and co-author of an upcoming book on jihadist recruitment of youngsters, says ISIS groomers are becoming ever more skilful at exploiting the vulnerabilities and confusion of Western teenagers, and Bloom, too, says they are luring them with techniques straight out of the pedophile playbook. They match online recruiters with prey in terms of age and nationality and gender—except with the older boys, who tend to be targeted by older Western women recruits, who seek to develop a romantic bond.

“The very young girls, say under 16 years old, tend to be on social media with other British women who are already in the Islamic State,” says Bloom. “It would be kind of creepy for the older male jihadists to be chatting online with teenage girls and might frighten them off. So the Western women already in Syria are acting as intermediaries, or what is known as ‘deviant peers,’ to encourage the possible recruits to let down their guard.”

Then they make the potential recruits feel that their enlistment is consensual. “There is this back and forth on social media to develop a rapport, to distance them from their families.” And to indulge teenage fantasies, they play with their sense of alienation and their urge to keep secrets.

Bloom singles out the importance of Aqsa Mahmood, a 21-year-old who was raised in a well-heeled Glasgow suburb and attended an exclusive Scottish girls’ school before joining ISIS last year. She has been named by British police as one of ISIS’s best online female recruiters, although her family say that in a recent communication to them she denied any involvement in recruiting three British schoolgirls who fled their east London homes in February and, without being challenged, flew from a London airport, crossing days later into Syria close to the Turkish border town of Urfa.

Last month, the FBI and U.S. Homeland Security Department issued a joint public alarm warning that ISIS’s marketing is resonating with young Western Muslims. The alert advised local and state agencies that ISIS is having success with social media recruitment campaigns.

In recent months a growing number of Western teenagers have either fled their Western homes to join ISIS or have had their plans disrupted when they tried to travel to Syria to join ISIS and to fight for the group or to marry a jihadist. In March, a high school student from Northern Virginia was taken into custody for assisting a friend to travel to Syria.

And last October three Syria-bound suburban Denver girls ranging in age from 15 to 17 were intercepted in Frankfurt and returned to the States. The two Somali sisters and a Sudanese friend stole cash from their parents to buy their plane tickets and until their departure had seemed typical American Muslim teenagers focused more on movies and mall expeditions than fundamentalism and jihad.

There are no firm figures on the number of Western teenagers who have fallen prey to ISIS. At least 15 minors from Belgium have been documented by Pieter Van Ostaeyen for the website Jihadology as having joined ISIS. The youngest, Younes Abaaoud, was just 13 years old when he left Brussels along with his 27-year-old brother last spring.

Earlier this year a 13-year-old French boy, now known as Abu Bakr al-Faransi, originally from Strasbourg, earned the unfortunate distinction of becoming the youngest jihadist (so far) to die fighting for the Islamic State in Syria. He was killed while on patrol near the western Syrian city of Homs and was described by a jihadist to French author David Thomson as “a good child and determined.”

As de-radicalization experts and psychologists grapple with the mindset of young Westerners lured into jihadist ranks, there is still no consensus among Western counter-terrorism experts on how to combat the jihadists’ sophisticated use of the Internet and their skill in radicalizing, grooming, and recruiting. The jihadist recruiters use a variety of online platforms: They make initial contact on Twitter and Facebook, then direct would-be recruits to other social media sites like Sharespot or Kick for the grooming to continue.

Radicalization can be accomplished in weeks. And every time it happens it has enormous shock value.

According to Bloom, online recruitment seems especially successful when it comes to teenage girls. Online recruitment has not been so obvious with young teenage boys—those who have been recruited online have been in their late teens or early 20s. Most of the teenage boys from Western countries who have turned up in Syria have accompanied their older brothers or arrived with whole family units. “I have not seen many instances where it is the 14-year-old boy who has been recruited online,” says Bloom.

Western governments have tried to employ online countermeasures—in the U.S. authorities have enlisted Islamic rap groups to help and they mounted a social media offensive against ISIS and al Qaeda aimed at ridiculing the militants’ sophisticated messaging with blunt sarcasm. But doubts have persisted since about the effectiveness of the offensive and whether the State Department is the right messenger.

Former British prosecutor Afzal argues governments need to mobilize young Muslim professionals to “show these potential radicals what their lives could be.” He adds: “They don’t want to hear from men with long beards, they don’t want to hear from faith leaders… We need to engage with the sorts of young people who can stop radicalization at source. It’s a bit like drug addiction. Telling them ‘It’s bad for you’ or calling the police on them is not going to solve the problem, unless it is too serious to wait. The message would have much more power if it came from recovering ‘addicts’ and other youths from their own communities that they can see as role models.”

Bloom agrees, arguing disillusioned returning fighters should be used to carry the counter-jihadist message.

And, she argues, contradictions within ISIS’s own propaganda should be highlighted. There is a big difference between the group’s Arab-language and English-language marketing, especially for women. “The English-language propaganda often implies they will have an exciting lifestyle, they will be like a Disney princess. But they will never have that kind of role in the caliphate—the moment they arrive they are married off. So they think it will be exciting and adventurous and they will be able to contribute. I think there is an element with some of these girls, and it is perverted of course, that they will be able to help with Syrian children or something, they think they will be doing something altruistic.”