The third attacker who terrorized Paris' Bataclan concert hall has been identified as a Frenchman who left for Syria in 2013, two French officials said Wednesday, heightening fears of what increasingly appears to be an entirely homegrown European plot.

Foued Mohamed-Aggad left Strasbourg for Syria in late 2013, a French judicial official said, at a time when a group of about a dozen young men from the eastern city left for the war zone. Some returned of their own will — including his brother — telling investigators they were disgusted by what they had seen. The Frenchman believed to have recruited them, Mourad Fares, is also under arrest. All are charged with terror-related offenses and face trial.

The officials spoke on condition of anonymity to provide details of the ongoing investigation.

All the Nov. 13 attackers identified so far have been from France or Belgium, native French speakers who joined Islamic State extremists in Syria. The Bataclan attackers, who carried automatic weapons and wore suicide vests, were responsible for the worst of the carnage. Of the 130 killed in Paris that night, nearly three-quarters died in the concert venue.

The other two attackers, Omar Ismail Mostefai and Samy Amimour, were also French. Two of the three gunmen detonated their explosives when police special forces moved in, while the third was shot by an officer and his explosives went off.

There is still identification work for the police to do. One of the attackers, who was killed Nov. 18 in a police raid on a hideout, remains entirely unidentified. Two of the suicide bombers at the French national stadium carried Syrian passports that are believed to be fake.

Attackers who struck the city that night included three suicide bombers at the stadium, a squad of commandos who shot up bars and restaurants, a suicide bomber at a restaurant and the three gunmen at the Bataclan.