Editor's note: This story was originally published Nov. 28, 2014. We are repromoting it following the attack on the Paris magazine Charlie Hebdo for background and context. The Islamic State has not claimed responsibility for the Paris shootings.
THE HAGUE, Netherlands — Blowback is the buzzword spreading a chill through the security forces of Europe right now.
It refers to fear of a new wave of terrorism emerging out of the carnage in the Middle East as fanatics among the up to 3,000 Europe-raised fighters serving with the Islamic State (IS) start to filter back home.
French Prime Minister Manuel Valls has called the threat from radicalized returnees from the Syrian war as "the greatest danger that we must face in the coming years." His British counterpart David Cameron describes it as "the most serious threat to Britain’s security that there is today.”
One of those at the heart of Europe's efforts to counter that threat is Will van Gemert. He took over as Europol's deputy director for operations in May after years of service with the Dutch police and intelligence service.
He has no illusions about the nature of the blowback threat.
"It's not hypothetical situation. It's a real situation, these people are coming back," van Gemert said during an interview in his office high in the distinctive four-tower headquarters of the European police agency.
"Because of the activities going on now in the conflict zone you can imagine there will be an increase in the numbers of people coming back."
Van Gemert points to the gun attack on the Jewish Museum in Brussels, Belgium, in May that killed four people. The suspect, a French Muslim called Mehdi Nemmouche is believed to have spent a several months serving with Islamist militants in Syria before returning to Europe.
For the moment such "lone wolf" attacks are the biggest danger posed by returnees from the Syrian conflict, van Gemert says.
"And it's the most difficult danger, to be honest, because there is no group," making it harder to detect in advance, he warns. "The lone wolf is very successful compared to others … that's the trend that we see now, as in Brussels, but also in London, other places – individuals."
Since the United States and other allies began airstrikes against IS, also known as ISIS or ISIL, the radical group has stepped up appeals for its supporters to strike against targets in the West.
A French Muslim convert named Mickael dos Santos, identified by security forces as one of the IS militants who decapitated 18 captured Syrian soldiers this month, had earlier appeared in a video appealing for "all the brothers that live in France" to "kill any civilians."
"The focus of ISIS is trying to convince people they should do something in a way that contributes to their cause and you've seen how devastating a simple attack can be," says van Gemert. "There is an offensive calling on foreign fighters, but also on Muslims in general, to act against the … countries involved (in air strikes against ISIS)."
That does not mean the threat of larger, coordinated attacks has gone away.
Counter-terrorist experts fear IS leader Abu Bakr al-Baghdadi wants to stage a 9/11 of his own to firm up his ambitions to succeed Osama Bin Laden as a global jihadist figurehead.
Formed in the 1990s, Europol has 850 staff working at its headquarters in The Hague to coordinate and support the work of law enforcement agencies in the 28 European Union nations — and partners like the United States — in the fight against terrorism and organized crime.
The agency works on about 18,000 cross-border investigations every year.
When GlobalPost visited this week, officers from around Europe were gathered for seminars on white-collar crime and online pedophile activity. An exhibition in the lobby featured equipment seized from narcotics labs.
Although it listed just seven people as killed by terrorists in the EU last year, Europol's annual report on terrorism released in May warns “in the wake of the Syrian conflict, the threat to the EU is likely to increase exponentially.”
Early this year the organization set up a dedicated "focal point" to receive and share information from ongoing investigations into the foreign fighter threat by agencies across Europe.
"The amount of contributions that we get from countries is increasing very strongly and it goes into multiple hundreds of messages during the last months," van Gemert says.
From that mass of information, Europol experts seek to build an overview of the situation, looking at trends on the type of people recruited by the IS, the routes they take into the Middle East conflict zones, support structures for the Islamist fighters, and the role of social media in radicalization and recruitment.
"All the ongoing investigations, ongoing intelligence that's coming in is put it into our system and it's our task … to see if there are any cross matches to be made on names, on phone numbers, on places, on anything you can imagine in this field," van Gemert explains.
"It's not enough, as a law enforcement agency or an intelligence service in one member state, to look at your own fighters, because (the EU's system of open internal borders) means anyone can come back and attack that country also, so there's a need for a role such as Europol is offering."
Terrorism experts acknowledge increased cooperation among forces in Europe is having an impact, but say more needs to be done to ensure information is shared across borders and domestically among agencies.
"We underestimated the phenomenon, and therefore it wasn't a priority, party because of institutional constraints, agencies not cooperating, not sharing information, a lot of it is secret and kept in the vaults," says Mark Singleton, director of the International Center for Counter-Terrorism, a think tank based in The Hague.
"The good news is that there are instruments that exist within Europe that allow an exchange of experience, " he told GlobalPost.
Singleton fears however that the current level of outrage and fear over IS's ultra-violent tactics could trigger a backlash by the authorities that leads to further radicalization among Muslim youths in Europe.
"The rhetoric unfortunately in parliament and elsewhere, in the media, is one of clampdown and repression," he cautions. "There should be a greater effort toward community level activities …
if we start ignoring or diminishing that part and instead focus more on criminalization of acts or even intentions, then we are maybe betting on the wrong horse."
Europol is aware of those risks.
Van Gemert says law enforcement officers in Europe are also worried that ethnic and sectarian violence in the Middle East could spill over into conflict within communities in Europe, or that Muslim minorities could be targeted by violence from far-right extremists.
"It's not only about judicial policy, if you want to get people to prevent radicalization, there is also a social part, a preventive part," he says. "Police services realize they need to get into those communities. Now it's not only about policing, it's also about youth working, it's about social care, about communities, they should be involved also. That's something that should be part of our strategic plan."
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