Two Tunisian citizens accused of being behind the recent murder of the U.S. ambassador to Libya in Benghazi were detained by police at Istanbul Atatürk Airport while trying to enter Turkey with fake passports, Hurriyet Daily News reported citing private channel Kanal D.

The suspects, who were not identified, were detained by members of Turkey’s anti-terrorism squad and subsequently taken to the Istanbul Police Department in the city’s Fatih district for questioning.

Envoy Chris Stevens, as well as three other American diplomatic staff, were killed on Sept 11 during a violent protest in Benghazi over “The Innocence of Muslims,” a U.S.-made film that mocks Islam.