Story highlights

The most pressing task is to identify the ISIS cells already in Europe and the relationships between them

Investigators are looking back at critical moments when key terror figures might have been stopped

Serving and former U.S. officials have been candidly critical of European security shortcomings

CNN  — 

First came the breakthrough: the arrest of Salah Abdeslam last Friday in the Brussels suburb of Molenbeek. Then came the catastrophe: a sophisticated attack in two high-profile locations involving a cell of at least five suspected terrorists.

For the Belgian authorities, it was a case of one step forward and many steps back in just a few days.

In the race to identify and apprehend what appear to be loosely connected cells in and around Brussels, Belgian authorities often seem to be struggling to join the dots. And they are not alone.

Multiple ISIS plots being planned in Europe, investigators say

Across Europe, security agencies are scrambling to keep up as ISIS opens a new front on the continent, involving dozens and perhaps hundreds of trained operatives.

Governments are playing catch-up in intelligence sharing, tackling the supply of illicit weapons, improving the tracking of suspects and deradicalization initiatives.

Rob Wainwright, the director of the European Police Agency often called Europol, told CNN Thursday: “The fragmented intelligence picture around this dispersed community of suspected terrorists is very challenging for European authorities.” Europol has the job of assimilating the work of more than 600 agencies across the European Union.

Surprises pop up

The most pressing task is to identify the ISIS cells already in Europe and the relationships between them. But Abdeslam – captured in Brussels last week and the only survivor among the Paris attackers – is no longer cooperating with Belgian investigators, according to his attorneys.

It’s not known whether Mohamed Bakkali, suspected of being one of the leading figures in the Paris plot, has provided any information. He was arrested at the end of November.

Last week, as part of their long search for Abdeslam, Belgian police descended on a property in the Forest suburb. They believed it was empty but might provide some forensic evidence. Instead, they ran into a gunfight and shot dead a 35-year old Algerian called Mohamed Belkaid. Two others escaped the property.

Only then did they establish that Belkaid was one and the same as Samir Bouzid, a name he had used to travel across Europe like from Syria last year with Salah Abdeslam. As Bouzid, he had also sent money to the cousin of Abdelhamid Abaaoud, who was killed in the French police raid on an apartment in Paris last November. An arrest warrant for “Bouzid” was issued in November, after surveillance images were circulated of him at a Western Union office.

Profiles of the Brussels terror suspects

Najim Laachraoui

And then there’s the man who accompanied Belkaid to the Western Union office. He went under the alias Soufiane Kayal.

It only emerged last week that he was really Najim Laachraoui, suspected of being involved in making the bombs for the Paris attackers and thought to have been one of the suicide bombers at Brussels airport. Laachraoui had a college education in electromechanics and the authorities knew he had gone to Syria in 2013. He was the subject of an international arrest warrant in 2014, but he managed to return to Belgium using his alias.

Belkaid and Laachraoui are believed to have been the quarter-masters of the Paris attacks, in contact with the Bataclan group as they began their attack.

Exemplars of the new threat

They exemplify the new threat: senior members of cells that include bomb-making, transport and financial functions to plan complex attacks in more than one location simultaneously.

The scale of their ambitions was indicated by the discovery of more than 30 pounds (14 kilograms) of TATP explosives and other bomb-making ingredients from the house in Schaerbeck that the bombers left early Tuesday morning.

What we know about the Brussels attacks

The fact that Abdeslam moved among safe-houses in the Brussels area for more than 120 days suggests Belgian authorities have few informants in Muslim communities.

After the Paris attacks, French officials grumbled about how much of the preparation was done in Belgium. Finance Minister Michel Sapin reopened the wounds Wednesday when he said there was a “lack of will on the part of some Belgian authorities, perhaps a naivety.” Sapin said Belgium had failed to integrate its immigrant population.

But the French Prime Minister Manuel Valls suggested the problem went far beyond Belgium, saying Europe had closed its eyes “to the rise of extremist Salafist ideas in neighborhoods where a mix of drug trafficking and radical Islam have led youth astray.”

The sharing problem

Khalid El Bakraoui

One of the problems for authorities across Europe is the number of suspects that have returned from Syria with new identities secured on high-quality forged documents that have been used to rent property or cars and send money.

Khalid El Bakraoui, who was the suicide bomber on the Brussels metro Tuesday, had rented the Brussels apartment raided last week under a false name and another property used in the preparation of bombs for the Paris attack. Both he and his brother Ibrahim were well known to police for a record of violent crime involving weapons.

ISIS is believed to have a supply of blank Syrian passports seized from government offices during its advance last year. At least two of the Paris attackers entered Europe on fake Syrian passports.

Serving and former U.S. officials have been candidly critical of European security shortcomings – comparing it to the silo mentality of U.S. agencies before 9/11. They say there is too little sharing of intelligence across and even within borders. Former Secretary of State Hillary Clinton entered the debate Wednesday, reviving an old U.S. complaint that European banks could do more to stop terrorist financing.

And she added: “Many European nations don’t even alert each other when they turn away a suspected jihadist at the border or when a passport is stolen… It’s actually easier for the United States to get flight manifests from EU nations than it is for EU nations to get them from their own neighbors.”

“It’s time to make good on the promise of establishing a new unified European border and coast guard to strengthen the continent’s external borders,” Clinton said in a speech in California.

Balancing security and freedom

The European Union has been examining the sharing of passenger information for six years. The European Parliament is due to consider the issue in April, but some members oppose the idea on privacy grounds. At the heart of the problem is the sharing of information on Europe-wide databases.

“That will require difficult discussions with European Parliament, because we’re sensitive about balance between security and freedom,” de Kerchove said.

Meeting in Brussels on Thursday, European interior ministers promised to accelerate work on integrating those databases and a European wide automated fingerprint recognition system. Experts from member states will be drafted in to the European Counter Terrorism Center. But many of the ministers’ recommendations will have to go to the next EU summit, which is in June.

Why Belgium? Five reasons why the terrorists struck there

Speaking with CNN’s Christiane Amanpour on Wednesday, the EU’s Counter-Terrorism Chief Gilles de Kerchove acknowledged problems in getting member states to act. “I do my best to put pressure, to confront them with blunt figures, and we are making progress, but not quickly enough.”

Ibrahim al Bakraoui

Turkish officials have also complained that would-be jihadists from Europe they have identified and deported have subsequently been released. One of them: Ibrahim al Bakraoui, who set off a suicide bomb at Brussels airport Tuesday. Turkish President Recep Tayyip Erdogan said Wednesday he had been deported from the Turkish border town of Gaziantep back to Europe.

“Despite our warning that this person was a foreign terrorist fighter, Belgium authorities couldn’t find a link to terrorism,” he said.

Belgian Interior Minister Jan Jambon acknowledged Thursday that it was “justified that people ask questions – that people ask how is it possible that someone was released early, and we missed a chance when he was in Turkey to detain him.” On Thursday, Jambon and Belgium’s justice minister offered their resignations over their failure to track Bakraoui but were asked by Prime Minister Charles Michel to stay on.

Turkey claimed last year it had flagged to French authorities one of the men who would later take part in the Paris attacks but received no response.

‘Open’ Europe at risk

European governments have begun to grasp the urgency of the challenge.

Belgium has doubled the budget for its intelligence services and introduced legislation to detain terror suspects without charge for longer than previously; France introduced a state of emergency and provided police with new powers. But there is a sense that European governments are behind the curve, struggling to cope with a surge in terrorism and a flood of migrants.

The vision of an open Europe enshrined in the Schengen Agreement of 1985 is at risk amid a brittle public mood. Valls said as much Wednesday. “If populism [in Europe] is on the rise, it’s because words are not translated into deeds,” he warned.

Right-wing parties in Germany, France and Britain have used the infiltration of terrorists among the surge of migrants to demand tougher curbs on the influx. And the recent provincial elections in Germany indicate the message has resonated with some voters. The anti-immigration AfD (Alternative fur Deutschlan) party seeing a surge of support in three states.

The European Union has agreed to a deal with Turkey that would allow Turkish nationals to travel visa-free to the European Union in exchange for closer Turkish co-operation in handling the migrant crisis. That in turn has unsettled many Europeans, with a poll for the ZDF network last week showing that 79% of Germans doubted Turkey would uphold its end of the bargain.

Another terror attack would further sour the mood as well as undermine the foundations of an open, tolerant and multicultural Europe. And that’s just what ISIS wants.