They chose the perfect moment. Just as Europe was letting out a sigh of relief, having captured one of the Paris terrorists after months of pursuit, the bombers detonated their explosives. The signal sent by the arrest was that Islamic State (IS) is defeatable. But the Brussels attack tells us that isn't the case. Just when you think you've beaten us, we'll strike you right in the heart.
Investigators and intelligence agencies both agree that preparations for the attacks in Brussels must have begun long ago. The Belgian bombs thus heralded a new approach for Islamic State in Europe -- one that does not bode well for those trying to prevent acts of terrorism -- because the threat is no longer limited to individuals known to the police or already on wanted lists, but also comes from those in the shadows in the second or third rank. Even jihadists who have not yet been identified by officials are now capable of striking.
This approach reflects the one used in IS' main battle grounds of Syria and Iraq. For some time there, unsuspected aggressors, who have been discreetly trained, have infiltrated targeted circles and built up long-term sleeper cells. Or men from regions neighboring a target are recruited to wait and attack at the right moment.
This is a modus operandi that has been employed by terrorists against prominent and often well-defended opponents multiple times -- it's how Abu Khalid al Suri, the Syrian emissary for al-Qaida boss Aiman al-Zawahiri, was betrayed by one of his own employees and killed in early 2014 by IS despite all possible protective measures being taken at his top secret hideout.
A rebel commander who had fled after Islamic State had taken over Raqqa was abducted by his own driver in Turkey, who was working under the orders of IS. And the founder of the secret activist network Raqqa Is Being Slaughtered Silently was massacred in his apartment in the Turkish city of Sanliurfa by an IS agent who had infiltrated the opponents months before, posing as a supporter.
The people behind this terror are proving to be surprisingly farsighted, patient planners and not rash actors -- and this applies in both Europe and Syria. This is the new and long underestimated side of IS.
The length Islamic State goes to in order to install sleeper cells is illustrated by a lesser-known case -- one in which IS attempted to infiltrate opposition forces.
Jamil Mahmoud, a young Kurdish man from Afrin who worked as a furniture painter in Beirut, was selected to be inserted into the ranks of the People's Protection Units (YPG) in the northern Syrian district where he had come from. Once his recruiters were confident enough that he would act in their interests, Mahmoud was smuggled through the harbor in Tripoli into Turkey, without ever having to show his passport.
From the sea, he was driven inland for four hours, the Kurd later told SPIEGEL. "Until we got to a large, isolated farmhouse. There were around 25 men there, Arabs and Turks. We were trained in the use of Kalashnikovs and Glock pistols."
They never left their camp. But the area of Gaziantep came up often in conversation. After two months, he was assigned to join the YPG militia in Afrin (a group close to the Kurdistan Workers' Party, or PKK) and told to await further orders. "They said simply they would always be nearby and that they would get in contact when it was time to take action." Mahmoud was driven to the border, whereupon he traveled to Afrin and joined the militia, as ordered. After a few months, however, he handed himself in to to the Kurdish authorities -- before the order to strike came through.
Sleeper Cells in Europe
IS' behavior is in many ways more like that of a secret service than of animated fanatics. Al-Qaida committed its attacks as its raison d'etre, the result being that there were no subsequent attacks far outside their usual theaters of war following their acts of violence on New York and Washington in 2001, on Casablanca, Madrid, Amman and elsewhere. Al-Qaida had acted, not reacted. But IS appears capable of doing so.
Testimony from deserters suggests the terror organization began establishing sleeper cells in multiple European countries early on, in Turkey in particular. According to the former IS fighters, they are made up of men who aren't on any watch lists. This enables IS to elude the vulnerability suffered by many based in Europe -- namely that they are known terrorists. The biographies of many terrorists are very similar: an early period of radicalization precedes a period of preparation just before an attack. By this point, however, many are already known to the authorities as dangerous and are subsequently often placed under surveillance. This included the Belgians who, in January 2015 wanted to attack police stations in Brussels immediately after the Charlie Hebdo massacre. Apartments, telephones and cars were bugged -- the authorities always had a clear picture of what was going on.
Attacks could repeatedly be thwarted mostly because the aggressors had left behind traces. Just after the July 2005 attacks on London, a British investigator warned that investigations placed too little emphasis on terrorists acting below the security services' radar. At that time, most of the attention had been focused on "homegrown terrorists," young men who radicalized themselves without even coming into contact with the al-Qaida leadership or prominent hate preachers. This category applied to each of the four men who blew themselves up in London.
Terrorism has become more professional since then. IS' masterminds now build up sleeper cell networks from an early stage in order to attack without hindrance at any chosen moment. That they are doing so in Syria is well documented. And that they are doing the same in Europe is very probable.