PARIS (AP) — French authorities filed preliminary charges Friday against the brother of a Tunisian man who stabbed to death two young women in the city of Marseille.

Anis Hanachi was transferred to France from Italy on Thursday and appeared Friday before an investigating judge, according to a French judicial official.

The judge handed down preliminary charges of criminal association with a terrorist enterprise with a view to committing an attack, the official said. The official spoke under condition of anonymity due to an ongoing investigation.

Preliminary charges under French law mean investigators have strong reason to believe a crime was committed, but allow further time for investigation.

Hanachi, 25, was arrested last month on an international warrant issued by French authorities accusing him of involvement in the Oct. 1 Marseille train station attack and of international terrorism.

The brother, who has fought in Syria, is suspected of having radicalized the attacker, and may have had a role in organizing the attack. The attacker, 29-year-old Ahmed Hanachi, who was shot dead after the attack.

The Islamic State group claimed responsibility though French authorities have not publicly confirmed a link with the extremist group.