From IJReview: A passport and a fingerprint from a Greek database allowed authorities to trace the movements of one of the suicide bombers from Paris. Working together, French and Greek authorities were able to figure out that Ahmad al-Mohammad had registered as a Syrian immigrant on the island of Lesbos a month before the attack.
“If they are not already registered in the database, it’s nearly impossible.”
Ahmad al-Mohammad was able to be identified as a terrorist only after the fact. His fingerprint was taken and he was registered when he passed through the processing center. At the time, he was considered to be a fleeing refugee along with everyone else.
A European official, who insisted on anonymity, further commented on the problem:
“In any event, this proves that the unchecked flow poses an unequalled challenge for European security. We simply don’t know who is coming through.”
All of these European authorities, dealing with the deluge of refugees coming from the Middle East, are directly confronting the same sorts of issues that the United States is facing.