After the bombs and Kalashnikov fire of the Paris attacks, a mere document — a passport — found near the body of an attacker is generating a new wave of dread throughout Europe and beyond.

But whether the document ended up there by chance, or was part of an elaborate plot to sow panic, is not clear. Regardless of the answer, the passport has played into the ISIS group’s hands by raising concerns that militants may be marching alongside the thousands of asylum seekers flowing into Europe.

That possibility is redefining the debate over immigration in Europe and even the United States, and prompting a backlash against Muslim refugees.

The far-right French leader Marine Le Pen called for an immediate end to the flow of migrants into France, while across the Atlantic about half of US governors are taking steps to prevent absorbing Syrian refugees in their states, citing the passport.

“This terrorist attack will clearly change Europe’s refugee policies and how the arrivals in Europe are treated,” said Konrad Pedziwiatr, a sociologist and expert on Islam in Europe at the Krakow University of Economics.

A passport bearing the name of Ahmad Al Mohammad, 25, was found near one of the suicide bombers who blew himself up outside the Stade de France football stadium.

The passport’s authenticity has not been determined, but fingerprints of the attacker match those taken by Greece and Serbia. The other attackers who have been identified so far are all European citizens.

The oddness that a passport, an intact one, was found near a man who blew himself up is creating suspicions that it is part of a plan by the ISIS to create a backlash against the refugees.“I have never heard of terrorists carrying passports with them,” Mr Pedziwiatr said.