The prosecutor had demanded the arrests of 16 Syrian suspects and sent them to Istanbul's Çağlayan Courthouse on Jan. 17 following police questioning. Separate proceedings against a 17th suspect - a minor - were still ongoing.
Meanwhile, the other six suspects were released under judicial control.
The Islamic State (IS) suicide bomber who killed the 10 German tourists by blowing himself up in Istanbul's touristic Sultanahmet Square was identified as a Syrian citizen born in Saudi Arabia who recently appealed to a district directorate of migration management for asylum in Turkey. The bomber set off the explosion just steps away from Istanbul's historic Blue Mosque.
The bomber, identified as 28-year-old Nabil Fadli, applied for asylum at the Zeytinburnu Migration Management Directorate in the Istanbul district on Jan. 5, security sources said.
Gerhard Günther Höppner, Steffen Höppner, Rudolf Krollman, Hiltrud Krollman, Karin Erika Franke-Dütz, Rüdiger Karl Faber, Marianne Faber, Gernot Eike Mildner, Adolf Jurgen Glorius and Rudiger Becker were all killed in Fadli's attack.