There are good reasons to wait for the full facts instead of jumping to the conclusion that Isis infiltrators are exploiting Europe’s refugee crisis

One of the most chilling details from the Paris attacks is that the passport of a Syrian refugee was found on or near the body of a dead suicide bomber. The Greek government has subsequently said that someone using the passport was among the refugees who landed in the Greek islands in early October, and the Serbian government says the passport was again used to cross its southern border a few days later.

This development has increased fears of Isis infiltrators among the thousands of desperate refugees arriving in Europe. Allies of the German chancellor, Angela Merkel, have voiced security concerns over her open-door policy and one, the Bavarian finance minister Markus Söder, told a German newspaper: “The days of uncontrolled immigration and illegal entry can’t continue just like that. Paris changes everything.”

The new government in Poland is using the news as a reason to back out of an agreement to take in several thousand Syrians. And the front page of the British newspaper the Mail on Sunday stated definitively that the attackers “sneaked into Europe as fake Syrian refugees”.

These fears should not be dismissed out of hand. Thousands of refugees arrive on the Greek islands every day. While each has to be registered before they can make it to the Greek mainland, the process is a brief formality rather than a lengthy investigation. In registrations witnessed by the Guardian during the summer, refugees simply presented identification to the Greek authorities, before being allowed to leave minutes later without anything like a background check.

Since October, each arrival has also been fingerprinted but officials still do not have the time nor the resources to assess whether or not they’re connected to militant groups. Should a would-be terrorist want to reach Europe via the Greek islands, it would be relatively simple to do.

But there are several reasons why it’s worth waiting until all the facts are known before making too strong a link between the attacks and the refugee crisis. The first is a general one: on at least 12 occasions, Isis has actually criticised refugees for fleeing to Europe. “For those who want to blame the attacks on Paris on refugees, you might want to get your facts straight,” wrote Aaron Zelin, an analyst of jihad, in an online commentary about the 12 outbursts. “The reality is, [Isis] loathes that individuals are fleeing Syria for Europe. It undermines [Isis’s] message that its self-styled caliphate is a refuge.” It’s therefore unlikely that the vast majority of Syrians fleeing to Europe are Isis supporters, since their actions are in obvious contravention of the group’s creed.

Paris attacks: what we know so far Read more

The second reason for caution is more specific. Investigators still need to verify the Syrian passport was carried by an attacker rather than a dead bystander (one Egyptian passport-holder initially believed to be an assailant turned out to be an injured victim). They will then need to be certain that the passport’s carrier was the same as the passport’s legitimate owner.

It’s possible that it was stolen. Since the possession of a Syrian passport makes it easier to claim asylum in Europe, there is a busy trade in stolen Syrian documents. Syrians interviewed on Greece’s border with Macedonia have described how they were mugged for their passports after leaving the Greek islands as they tried to make their way north through the Balkans. Such passports can be sold on for as much as several thousand euros, in a trade that the EU’s border agency acknowledges is a growing problem. Forgeries are also common; a Dutch journalist recently had one made in the name of his prime minister.

A third red flag is the fact that the passport concerned was found in the first place. Analysts find it strange that a bomber would remember to bring his passport on a mission, particularly one who does not intend to return alive. “Why would a jihadist who expressly rejects all notions of modern citizenship take his passport on a suicide mission?” tweeted Charlie Winter, an analyst focusing on Islamist extremism. “So it gets found.”

One theory is that Isis hopes to turn Europe against Syrian refugees. This would reinforce the idea of unresolvable divisions between east and west, and Christians and Muslims, and so persuade Syrians that Islamic State’s self-proclaimed caliphate is their best hope of protection. “You know what pissed off Islamist extremists the most about Europe?” summarised Iyad El-Baghdadi, an activist and jihadi-watcher, on Twitter. “It was watching their very humane, moral response to the refugee crisis.”

Whether the passport was planted, stolen, forged or genuine, investigators should find out the truth soon enough. But regardless of what they discover, a wider debate has now begun about the wisdom of letting so many unknown migrants enter Europe through its southern borders, and being allowed to move onwards through the continent with few restrictions. Already, there are calls to step up the policing of Greece’s maritime border with Turkey, and to block the passage of refugees entirely.

Such a strategy seems likely to fail. Europe is not nearly as isolated as Australia. An Australian-style policy of turning back boats would be impossible to enforce because Europe’s eastern shores lie less than six miles from where refugees set sail, rather than dozens. Instead, a more logical response would be to create an organised system of mass-resettlement from the Middle East itself.

This would not satisfy Europe’s populists: it would formalise rather than end the continent’s biggest wave of mass migration since the second world war. But it would enable Europe to screen refugees before they arrive; work out who they are and where they’re from; and decide where they should go, and when they should get there. If such a process can be completed for a large enough group of people, and in a swift enough fashion, it would help deter a majority of refugees from traipsing through Europe in the current chaotic way. It would also give European governments a better chance of weeding out potential bombers – a fact that some Syrian refugees have acknowledged themselves.

“Why make us all do this trip?” said a Syrian software developer, Maher Dahy, as he waited on the Croatian border in September. “Just organise it, give people visas so they can come on the plane. If you don’t, people will keep coming.”