Abaaoud's terrorist network in Paris, officials say, was distinct from the Brussels petty-crime ring, which did not carry out attacks in Europe but instead recruited fighters and funded their transit to the Middle East. But several of the Paris attackers also had criminal pasts. Two of them - Brahim Abdeslam, who blew himself up on November 13, and his brother, Salah Abdeslam, who is on the run - operated a cafe in Brussels that was shut down as recently as August due to drug-related activity.
A French official familiar with the Paris investigation also said forensic testing has uncovered traces of Captagon, a blend of amphetamine and theophylline, in the remains of several of the dead assailants despite the prohibition on intoxicants in Islam.
"This connection with the criminal world was not something that you could see with [Osama] bin Laden," said Mohammad-Mahmoud Ould Mohamedou, deputy director of the Geneva Centre for Security Policy. "You had a certain fundamentalism within the terror."
European jails have been breeding grounds of Islamist radicals for years, particularly in Belgium and France. But recently, criminality and extremism have become even more interwoven, with recruits' illegal behaviour continuing even after they are shown "the light" of radical Islam.
"Many of them live lives as hoodlums, had an epiphany, and turned religious, but these connections to criminality are not meant to disappear," said Peter Neumann, a radicalisation expert at King's College London. "I see this as an operational aspect of the Islamic State."
In one example of the new trend, a court in Cologne, Germany, has been hearing the case of eight men suspected of having robbed churches, schools and businesses between August 2011 and November 2014 to support Islamist fighters in Syria.
Few cases, though, better highlight the apparent links between criminality and radicalisation than the Brussels ring allegedly headed by Khalid Zerkani, a 42-year-old rotund and bearded Moroccan with alleged ties to Isis.
Known to his followers as "Papa Noel" - or Santa Claus - Zerkani, authorities say, doled out cash and presents to the wayward youths he recruited as thieves and prospective fighters. They would target train stations and tourists, stealing luggage, even shoplifting. The profits, officials say, went to help cover the costs of sending recruits from Europe to the battlefields of the Middle East.
Stealing is prohibited in Islam. But Isis followers have rationalised such activities by saying that they are targeting non-believers.
Officials say Zerkani has been tied to at least 30 to 40 people who left Belgium for Syria and Iraq.
One of his recruits, 21-year-old Youssef Bouamar, told authorities that Zerkani had encouraged him to steal luggage at train stations to finance "the Islamist cause". Zerkani appeared to target those who already had petty criminal records, wooing recruits at cafes and on the streets near unofficial mosques in Molenbeek, a Brussels neighbourhood with many North African immigrants.
Mohamed Karim Haddad, whose brother was recruited to fight in Syria, told officials that Zerkani was "a charlatan who manipulates young men or socially awkward men, for the wrong cause and probably for his own business". Belgian authorities arrested Zerkani in February 2014 and charged him with being a leader of a terrorist operation. He was convicted this year and sentenced to 12 years. He pleaded not guilty and is appealing the verdict.
Abaaoud was very familiar with "Papa Noel's" world. His family lived in Molenbeek at a time when Zerkani and his followers had become fixtures there. Abaaoud was linked to at least three of the network's members, according to intelligence documents, court records, police reports and more than a dozen interviews. He was convicted in absentia this year in the same trial as Zerkani, though authorities stopped short of saying that the men worked together. But a text authorities found on one of Zerkani's cellphones appears to reference Abaaoud by his nom de guerre in Syria, Abu Omar Soussi.
One of Abaaoud's younger brothers - Yassine Abaaoud - told authorities that his mother had once begged him to avoid Zerkani and his entourage.
"She was scared of them because of all the problems," Yassine said, according to court records.
The newer jihadist groups mark a shift, experts say, from older organisations like al-Qaeda that were far more strict in interpreting theology and used recruiting videos that were often rambling 45-minute sermons from bin Laden, the scion of a wealthy Saudi industrialist family. Isis uses showy internet propaganda to advertise the allure of a paradise where disenfranchised youths can feel a rush of adrenaline and enjoy the spoils of war.
"These are lower quality terrorists," said another senior European security official.
That hardly means they are less dangerous. Criminal links may be allowing the newer groups' members to more easily source weapons and cash in Europe, experts say.
There are other links between the ringleader of the Paris attacks and Zerkani's inner circle. A police search in February 2014, court records show, turned up Abaaoud's expired Moroccan passport in the Brussels apartment of one of Zerkani's followers.
Officials and Muslim leaders say Isis recruiters are appealing to young Muslims with criminal pasts because they make some of the best targets. They are often angry and alienated, like Farid, a slim, pale man in his 20s, the son of Moroccan immigrants who said Abaaoud was a friend.
He described the life of young Muslims in the district as hopeless, with many feeling stateless and confronting unemployment rates well above the national average. He and most of his friends, he said, had done jail time.
"We are revolting against this state and this society that never accepted us as Belgian," he said. "We are revolting against our parents and also their countries of origin.
I don't feel Belgian. I don't feel Moroccan. I think of myself as a Muslim, and that's how Abdelhamid saw himself." Washington Post - Bloomberg
