After 120 days on the run, Salah Abdeslam, accused of being part of the group that carried out the brutal attacks in Paris in November 2015, has finally been arrested.

He was found in the Molenbeek district of Brussels, where he lived and worked before the attacks. Despite countless police raids in recent months, Abdeslam managed to evade capture in his own neighbourhood.

In November 2015, he is suspected of being part of three well-organised groups of jihadists which attacked Paris, including bars, the Bataclan concert hall and the area around the Stade de France. They killed 130 people and most of the attackers also died.

Islamic State claimed a further attack in the 18th Arondissement which didn’t happen. It is not yet clear if this was to be carried out by Abdeslam.

He claims that he was going to blow himself up in the Stade de France, but changed his mind. One final attacker, Mohamed Abrini, remains on the run.

Hiding In Plain Sight

Salah Abdeslam’s brother, Brahim, was one of the Paris attackers who blew himself up near a café on Boulevard Voltaire. Acquaintances claim that both drank alcohol and sold drugs, were not known as regular attenders at the mosque, and had a background in petty crime.

Newspapers and anonymous “officials” have branded Molenbeek with a number of alarmist epithets. It’s a “terror capital”, a “jihadi breeding ground” and so on. It is a district of 100,000 people, with high rates of unemployment, especially among its young, multi-ethnic locals. It is home to a transient population.

1930s criminologists of the Chicago School would recognise Molenbeek immediately. This is a place where community institutions are dislocated, and where the unemployed can choose between drug addiction and a criminal career. The normal choice of rackets – drug dealing, confidence trickstering, prostitution, burglary and violence – have been joined by a new greasy pole: jihadism.

It is not Islam that is the problem in Molenbeek, but unemployment and poverty. It is difficult to police because young people move flats all the time and civil society is patchy. There are few genuine community leaders with whom these young people can work when they need support.

In such a district, it is not really surprising that it has taken so long to find Abdeslam. Partners for the police are hard to find. It’s not hard to imagine why his associates would have decided to shelter him rather than report him.

The more important question is how the whole network managed to evade detection before the attack. How much was this down to the sophistication of their methods and how much was it the result of police failures and open borders?

Highly Organised Operation

There was a large network behind the Paris attacks, not just the five-participant cell that was characteristic of terrorism in the 1960s and 70s. The New York Times, which has obtained a report by the French police, claims 18 people are in custody in six countries suspected of helping the attackers. This is in addition to the nine who are already dead.

Police in Molenbeek. EPA/Laurent Dubrule

They were well trained and able to carry out a co-ordinated attack in a number of different places, using both explosives and firearms, taking hostages and effectively confusing and hampering the police response. In the months leading up to the attack, they were able to slip in and out of Europe undetected, crossing both internal and external borders.

No email traces or evidence of online chats have been discovered. The attackers used phones once, then discarded them. In the Bataclan, they used hostages’ phones. They had clearly learnt from police investigations into previous attacks, again suggesting training and discipline.

According to the New York Times, a woman held hostage in the Bataclan saw one of the terrorists switch on a laptop, and that what appeared on the screen looked like gibberish – potentially meaning he was using encryption software.

There are legal and cultural problems with sharing information between security services, both within countries and across borders. There are problems transliterating Arabic names in different systems. There are problems sorting the wheat from the chaff in the intelligence.

It is always possible to recognise relevant intelligence with hindsight, but there are not enough resources to put all suspects under surveillance. It is also probable that individuals with petty criminal backgrounds have not been considered as dangerous as those with hardline ideological commitments.

Consequences For Europeans

The French prosecutor appears suspicious of the testimony Abdeslam has initially given to the Belgian police, given that he appears to have driven some of the attackers to the Stade de France.

It may be that both he and others were intended to survive and continue plans for further attacks, although events suggest improvisation played a part as well as planning. If so, it will be even more vital to discover how his communication systems operated.

There will be increased border checks, including at Schengen internal borders. There will be increased surveillance. There will be increased demands for access to the phone and email records of all citizens. There will be increased roll-out of CCTV across Europe.

But the lesson to learn from all this is that terrorists, just like criminals, change their modus operandi in response to changes by the security forces. The rest of us get inconvenienced, not the terrorists. The need is to keep the public onside – and not to further alienate marginal communities like Molenbeek.