After a series of six terrorist attacks in Paris on Friday night killed at least 129 people, investigators started searching Europe for information about the seven suicide bombers and others who may have helped plot the attacks.
French investigators identified Ismaël Omar Mostefaï, a 29-year-old French citizen, as one of the three suicide bombers taking hostages at the Bataclan concert hall Friday, The New York Times reports.
Ahmad Almohammad, 25, was reportedly the holder of a Syrian passport authorities say was found near a Paris attacker. Officials said he had passed through Greece and Serbia as part of Europe's flow of migrants, many of them refugees fleeing Syria and other war-torn countries.
On Saturday, authorities in a Paris suburb found three rifles in an abandoned vehicle they said may have been used as a getaway car. Three men have also been detained in Brussels and four at a border crossing in France for possible connections to the attacks, which the Islamic State has claimed responsibility for carrying out.