A court in Istanbul released the eight Büyükada meeting suspects late Wednesday pending trials in a hearing in Çağlayan Courthouse.
The suspects linked to several NGOs were detained at a meeting in July over terror group membership and aiding charges.
The suspects are Amnesty International's Turkey director, Veli Acu, German national Peter Frank Steudtner, Swedish national Ali Ghravi, and nine Turkish nationals, namely Taner Kılıç, Amnesty International's Turkey representative, İdil Eser, AI Turkey board member, Nalan Erkem and Özlem Dalkıran from Citizens Assembly, İlknur Üstün from Women's Coalition, Günal Kurşun from Human Rights Agenda Association, Nejat Taştan from the Association for Monitoring Equal Rights and former Association for Human Rights and Solidarity for the Oppressed activist Şeyhmus Özbekli. Three of the suspects are on trial without arrest.
The suspects were detained July 5 at a meeting in Büyükada of Istanbul's Princes' Islands.
In the indictment, the prosecutor charged the suspects with aiming to incite violent and chaotic mass public protests during main opposition Republican People's Party Chairman Kemal Kılıçdaroğlu's "Justice" march between June 15 and July 15.
Kılıçdaroğlu and fellow party members had walked from the capital Ankara to Istanbul to demand what they called "justice" for people detained for their links to terrorist groups, particularly FETÖ.
The indictment likened the planned protests to those in the Gezi Park riots of 2013.
Taner Kılıç, a representative of Amnesty International in Turkey, was detained earlier for using ByLock, an encrypted messaging app exclusively used by the Gülenist Terror Group (FETÖ), which is responsible of last year's failed coup attempt.
The indictment charged Kılıç with armed terror group membership, whereas the rest of the suspects were charged with aiding an armed terror group.
