Balkan authorities are tracking the travels of a man whose Syrian passport was found next to a dead suicide bomber at France's national stadium on Friday night.
Officials in Greece say the passport's owner entered the country on Oct. 3 through Leros, one of the eastern Aegean islands that tens of thousands of people fleeing war and poverty have been using as a gateway into the 28-nation European Union.
Serbian police say he registered at its border entry with the Former Yugoslav Republic of Macedonia on Oct. 7.
Croatian police say he was checked at a refugee center on Oct. 8. Police spokeswoman Helena Biocic said Sunday the man was not flagged as suspicious and continued his journey toward Hungary and Austria.
It is still not yet clear if the Syrian passport is fake or real, or if it belonged to the dead bomber. European officials say there is a brisk trade in fake Syrian passports to help people get refugee status in the EU.