Slideshow ( 2 images )

ROME (Reuters) - (This October 8 story has been refiled to correct names of Marseille attacker and his brother, which had been switched in previous story.)

Italian police said on Sunday they had arrested the brother of Ahmed Hannachi, the Tunisian man who killed two young women with a knife outside the Marseille train station a week ago in a suspected terrorist act.

An Italian anti-terrorism squad arrested 25-year-old Anis Hannachi in Ferrara, Italy, on Saturday evening on an international warrant issued by France, a police statement said.

On Oct. 1, Ahmed Hannachi shouted “Allahu Akbar” (God is greatest) as he killed the women, French police sources said.

Ahmed Hannachi was shot dead by a French soldier. The militant Islamic State group claimed responsibility for the attack, but did not name the assailant.

After what Italian police described as a “very complex” investigation, Anis Hannachi was tracked down in Italy, the statement said, and is being held on suspicion of complicity in his brother’s attack and membership in a terrorist group.

No other information was provided about the operation, which was coordinated with French judicial and anti-terrorism authorities, the statement said.