BELGIUM’S satisfaction at finding Salah Abdeslam, the man believed to have been the Islamic State (IS) logistics chief behind the Paris terror attacks, which took the lives of 130 people four months ago, was always likely to be fleeting. That it had taken so long to track Mr Abdeslam down was worrying. That he was found staying in the apartment of a friend’s mother in Molenbeek, the district of Brussels that is probably home to the highest concentration of jihadist sympathisers in Europe, is an indication of chronic intelligence failure on the part of Belgian’s State Security Service and the police.
But perhaps the biggest worry is the discovery that IS’s network in Belgium, and perhaps across Europe, is so extensive. To be able to conduct serial complex attacks—such as the multiple bombings in Brussels’ international airport and metro system, which killed at least 30 people on the morning of March 22nd—suggests IS can draw on perhaps hundreds of supporters, some of whom have reliable bomb-making expertise and know how to communicate securely.
Some will argue that the timing of the attacks on Brussels, coming so soon after the arrest of Mr Abdeslam, is a coincidence. But that probably underestimates the scale of the IS operation in Belgium. Indeed, Mr Abdeslam’s arrest may well have been the trigger for another cell to go into action with a plan that had been some weeks or months in preparation.
There are still hopes that Mr Abdeslam’s arrest and almost certain extradition to France will yield information that fills in the gaps in what is known about the Paris and Brussels attacks. But what has been learned so far by French investigators after the interrogation of witnesses and investigation of both the crime scenes and places where the terrorists had lived is disturbing enough.