Delefortrie stayed in Aleppo, Syria, for about five weeks, according to court papers, and while there he posed for photographs with weapons and posted them on his Facebook page, where he named as his employers Jabhat Al-Nusra (the Nusra Front, Al-Qaeda’s Syrian franchise) and “Revolusi [revolution] Dawlah Al-Islamiah [ISIL].” He said he told the court he returned to Belgium because he missed his wife and two children. Court documents noted that as a converted Muslim, he likely didn't enjoy much trust among the Syrian rebels.

Trained as a pastry chef, Delefortrie said he once worked in the restaurant; now his presence unnerves the owner, who avoids negative publicity generated by some of his erstwhile patrons. The meeting in the restaurant took place amid a tense atmosphere in the city. Military personnel patrolled the Jewish quarter in the aftermath of a foiled plot in the southern town of Verviers to attack police forces in February.

About 470 Belgians are estimated to be fighting in Syria — the most per capita of any Western European country, according to data compiled by Pieter Van Ostaeyen, a Belgian researcher. The extraordinarily high concentration of recruits to ISIL and other violent groups has put the country in the international spotlight, leaving policymakers searching for a strategy to combat extremism.

AlDe’emeh is intimately acquainted with the social milieu from which many of these recruits have emerged. Children of more than 150 nationalities play on a square outside his fourth-floor apartment in Molenbeek, Belgium, where two of the Verviers attackers were from. And two weeks of field research embedded with Jabhat Al-Nusra in Syria has provided him with rare insights into the mindset of young Europeans attracted to such organizations.

Delefortrie’s journey to an ISIL worldview hit a milestone in 2007, when he converted to Islam in search of the “more structured and quieter life” that had eluded him.

“You should have seen me before,” he said, although he was loath to talk about his past and abhors the tendency to reduce decisions to convert to Islam as a response to adversity. He said he has always been religious: His grandmother’s religious teachings and his time as an altar boy at Merksem’s Catholic St. Franciscus Church — where a church administrator says he attended Mass every Sunday from age 8 into early adolescence.

“Religion is a refuge. Religion is a salvation. So is it unusual that many people convert after they’ve experienced difficulties? No, of course not,” he said.

Since his conviction on terrorism charges, it hasn’t been easy for Delefortrie to find work. He said his midlength beard does not sit well with his new boss, who urged him to “trim it a bit” — comments that, along with his father’s racial slurs about “brown” Moroccans, are part of what he says is a barrage of continuous assaults on his Muslim identity.

“I have to defend myself all the time,” he said. “But why should I renounce my own identity for my job?”

Delefortrie’s conversion to Islam came in the diverse suburb of Merksem after befriending Moroccan neighbors, with whom he smoked weed and socialized. But he later distanced himself from them over their failure to adhere to his stricter interpretation of his new faith, reproaching them for adjusting to Western ways and practicing their religion passively.

Books guided Delefortrie’s search for truth, he said, and at the restaurant, AlDe’emeh handed him a 497-page study by Dutch researchers, “Islands in a Sea of Unbelief,” on the workings of activist networks such as Sharia4Belgium and others in the Netherlands and Germany. Delefortrie was interviewed as a research subject in the book, one of the tools that AlDe'emeh believes might help change his extreme views.

Sharia4Belgium gained notoriety in 2011 by calling for the implementation of Islamic law in Belgium and organizing protests against bans on headscarves in many public schools and on wearing full-face veils in public. By the time Belgian authorities shut down the group’s operations in 2012, the first member had left to fight in Syria. Many have followed, citing a desire to help out brothers, expressing feelings of injustice and answering calls to global jihad, they said in videos on the group’s YouTube channel. Delefortrie joined Sharia4Belgium four years after turning to Islam, which, he said, offers a path to improve the character of its adherents.

AlDe’emeh expressed sympathy for Delefortrie for the challenges and lack of institutional support he faced but encouraged him to build relationships and keep a job in order to re-establish a life in Belgian society. And he nudged Delefortrie to give up the illusory promise of finding a peaceful life in ISIL’s caliphate.

“In my efforts to help these youth channel their frustrations, I hope that I can at least prevent them from hurting themselves and others,” AlDe’emeh said. “Imagine someone flips tomorrow, then polarization will become stronger in society, and I don’t want that.”

The risk of young Belgians flipping and staging their own assaults was illustrated in January after the police raid in Verviers disrupted a plot by two former fighters to kill Belgian policemen a week after the Paris attacks at the offices of Charlie Hebdo and a kosher supermarket.

Raising the national terrorism-alert level to 3, the second-highest degree, Prime Minister Charles Michel’s right-wing government announced a 12-step counterterrorism plan that included measures to tighten the country’s laws and revoke the passport of citizens who travel to war zones in Iraq and Syria. Soldiers were deployed to protect potential targets, and Internal Affairs Minister Jan Jambon proposed legislation to revoke the Belgian citizenship of dual nationals who travel to Syria — the majority of them born in Belgium to Moroccan parents.

Finding the right mix of punitive and preventive measures has proved challenging for the authorities. But social workers and policymakers in the town of Vilvoorde, near Brussels, believe they have found an effective balance. Although 28 people from the town have gone to fight in Syria, not one has left since May 2014, according to Mayor Hans Bonte. As a result, the mayor receives invitations from as far away as Washington, D.C., and Columbus, Ohio, to share the town’s recipe for combating extremism.

Vilvoorde’s formula? Bringing parents, friends, mentors and security personnel together to map possible recruits’ emotional well-being and devise a plan to reintegrate them into the community. This “injection of warmth” is paired with theological guidance provided by experts in Islam who can help alter people’s extremist outlook, Bonte said. There is no cookie-cutter profile of foreign fighters, he added. Those who have left Belgium for Syria include men and women from diverse socioeconomic backgrounds, and their ages have ranged from 15 to 35. “What they all have in common is a feeling of rootlessness, of not belonging.”

Alienation and indoctrination are recurring themes in the stories of those lured to Syria, according to Vrije Universiteit Brussel researcher Bilal Benyaich. Sharia4Belgium encouraged its members to stop talking to their parents, quit school, grow a beard and wear traditional Islamic clothing, according to court documents, and it offered them a place in an alternative community.

Delefortrie recalled the sense of camaraderie that developed as he took part in everyday activities with the group — eating meals, going to lectures, studying and shopping. “We did everything together,” he said.

Young Belgians from immigrant backgrounds may have their feelings of exclusion compounded by discrimination in the Flemish labor market. A survey that made headlines last month found that two-thirds of temp agencies heed clients’ wishes to refrain from hiring cleaning personnel of immigrant descent. A feeling of not belonging is felt more keenly in Flanders, the affluent, northern part of the country, where the vast majority of Belgium’s foreign fighters originate, according to Bonte.

But the currents of alienation run deeper. Belgium’s secular traditions have relegated religion to the private sphere, which has left the country’s social workers and teachers poorly equipped to engage with communities of faith.

Some of these people believe religious individuals are stuck in a “magical world,” said Elke Vandeperre, a coordinator of Motief, an Antwerp-based nonprofit that recently received funding from the government to combat radicalization. Only 1.5 percent of social workers engaging with youth are of immigrant descent, according to Benyaich.

“The real prevention lies in taking a good look at ourselves," she said. "How can we make sure that these youth are stimulated in our educational system to think about how they want to contribute to society? If they permanently get the feeling of not being able to contribute from their own identity, things go wrong.”

Mosques haven’t proved particularly helpful in establishing connections with Belgium's at-risk youth, experts say. Most imams don’t speak Dutch and deliver their sermons in Arabic or Turkish at small, makeshift mosques that aren’t recognized by the government, according to Benyaich. Some of these youths, searching for answers their imams can't provide, then turn to the Internet, where extreme propaganda proliferates, according to AlDe’emeh.

But the key challenge facing social workers and the young people they work with is finding a way to integrate them into Belgian society — or at least to steer them away from the path of violence — without requiring them to cede their Muslim identity. “I couldn’t be myself anymore,” Delefortrie said about his decision to go to Syria. "If you can’t be yourself anymore and can’t say what you think, then it stops there. Then you have to leave.”