Trial of Salah Abdeslam in Paris attack begins in his hometown of Brussels on Monday

He is the mute survivor of the 10-man ISIS cell that terrorized Paris in November 2015, refusing all pleas to shed light on the attack that left 130 dead or another one in Brussels just four days after his arrest.

After nearly three years jailed in isolation and silence, Salah Abdeslam goes on trial Monday in his hometown of Brussels for a police shootout that he himself fled. The man who covered for his getaway with a spray of automatic gunfire died. Abdeslam's escape was short-lived — he was captured on March 18, 2016, in the same Brussels neighbourhood where he and many of his ISIS fighter colleagues had grown up.

Four days later, ISIS suicide attackers struck again, this time at the Brussels airport and subway. In all, that sprawling network of IS fighters killed 162 people in the two European capitals. Most of the extremists were French speakers, raised in one of the cities they struck. The plot's execution depended upon ISIS's success in wedding crime and religion.

Abdeslam, who along with his brother was suspected of dealing drugs from the bar they ran, is the starkest example of that convergence. But in Paris, the trial of three men accused of giving safe haven to the attackers also provides a revealing look at the intersection that made possible one of the deadliest terror attacks in Europe since the Second World War.

The operational commander of the cell was Abdelhamid Abaaoud, a petty criminal who used his home neighbourhood of Molenbeek in Brussels as a fertile recruiting ground for IS. Abaaoud even recruited his younger brother, then 14. But many of the young men who followed him into IS were small-time criminals themselves, part of the extremist organization's deliberate attempt to make use of "skills" that include accessing black market weapons, forging documents and handling covert logistics.

Drug dealer just 'doing a service'

When the night of carnage in Paris — Nov. 13, 2015 — was finally over, seven attackers were dead and three were on the run: Abdeslam, Abaaoud and another Molenbeek native named Chakib Akrouh. Abdeslam called friends in Brussels to drive through the night and pick him up. Abaaoud also called his cousin, Hasna Ait Belkacem, who lived in a suburb of Paris and vacillated between hard-line Islam and even harder drug use. She was happy to help. She called her dealer. He called another dealer.

It took a few days of sleeping under bushes, but for 150 euros wired from Belgium, they secured a room in the Paris neighbourhood of Saint-Denis, near the national stadium they had attacked on Nov. 13. In the pre-dawn hours of Nov. 18, frantic French investigators tipped off by a friend of Ait Belkacem tracked them to the building and sealed off the neighbourhood.

Abaaoud, Ait Belkacem and Akrouh all died when Akrouh detonated a suicide vest.

Just before his building crumbled to the ground, one of the drug dealers, Jawad Bendaoud, showed up to find out what was happening and explained on live television that he was just "doing a service" by renting out his room. With the cameras still rolling, Bendaoud was taken into custody.

At their trial, his fellow dealer, Mohammed Soumah, explained how he framed the world: Good citizens, delinquents, rapists and terrorists.

"Me, I don't fit in the terrorist box. I'm a thug, a scumbag," Soumah told the judge. But there he was sitting in the box for terrorism defendants in central Paris alongside Bendaoud. As for why neither man made the connection between the two Belgians desperate for a hideout amid a massive police manhunt and an outpouring of grief for France's 130 victims, Soumah had another explanation.

"The criminal life goes on," he said.

Criminals attracted to ISIS

But the lines between terrorists and criminals are less clear now than ever, said Peter Neumann, director of the International Centre for the Study of Radicalisation.

"ISIS is perhaps the first jihadist group that has explicitly targeted this demographic, and they've done it very consciously and especially in Europe," he said. "What we saw in Brussels and Paris — this is not an isolated case. This is actually reflecting the situation across Europe. If you go to Sweden, Norway, Holland, Germany, they will all tell you that 50 per cent plus of the people who have turned up travelling to Syria or involved in domestic plots have previous criminal convictions, often for petty crime."

On Friday, a Belgian career criminal was transferred into French custody over allegations that he housed the jihadi who attacked the Thalys high-speed train between Brussels and Paris. The suspect, Youssef Siraj, is also believed to have put up some of the Brussels attackers, according to the Belgian news site DH. The same group is also linked to a raid in the Belgian town of Verviers, where authorities say a jihadi cell was on the verge of a co-ordinated attack against police.

"We are coming to realize that Verviers, Thalys, Nov. 13, the attacks of March 22, it's a large and perhaps single operation of Daesh," Belgian federal prosecutor Frederic Van Leeuw said, using another term for ISIS. All were bound by ties of crime and extremism.

The jihadi who wired the money to pay Bendaoud and Soumah was himself a petty criminal in Sweden before joining the ISIS group, a thief who picked up firearms skills during his time in Syria named Mohamed Belkaid. It was also Belkaid who opened fire on Belgian police as they raided Abdeslam's Brussels hideout. He was shot dead in the March 15, 2016, raid.

Abdeslam escaped through a window over the rooftops.

He was traced to a cousin's apartment on March 18, 2016, near his Molenbeek home. Still more members of the cross-border ISIS cell struck Brussels on March 22, 2016, including the bomb-maker for both attacks. Thirty-two people were killed in Brussels, along with three suicide attackers.

Abdeslam has been imprisoned ever since. This week's trial marks the first time he has been seen in public since his capture.

According to the French network France Inter, Abdeslam stored a message in his computer similar to the farewells written by other jihadis ahead of suicide attacks.

In it, France Inter reported, he explained that his suicide belt malfunctioned in Paris and that, although he dreamed of going to Syria "upon reflection, I concluded that the best thing would be to finish the job with the brothers."