[13] In the acknowledgements of his 2018 book Talaat Pasha: Father of Modern Turkey, Architect of Genocide, historian Hans-Lukas Kieser states that Kavala's assistance was "critical to my successfully starting the research".
These include TEMA (Turkish Foundation for Combating Soil Erosion for Reforestation and the Protection of Natural Habitats), Helsinki Citizens' Assembly, and Center for Democracy and Reconciliation in Southeast Europe.
Kavala was a founding member of the Open Society Foundations in Turkey, an international grantmaking network created by the American-Hungarian billionaire George Soros.
[22] In an op-ed published in The New York Times, Kavala states: "It seems I was cast in this narrative because I was a board member of the Open Society Foundation in Turkey and because of my open—though not financial—support of the campaign to protect Gezi Park.
[22] On 25 October 2017, the newspaper Daily Sabah, close to the Erdoğan government, accused him of being a "business tycoon with a shady background" and having contacts with the "Gülenist Terror Group" (FETÖ).
[29] Article 309 ("attempts to abolish, replace or prevent the implementation of, through force and violence, the constitutional order of the republic of Turkey"[30]) was related to an investigation on the 2016 Turkish coup d'état attempt, and Article 312 ("the use of force and violence, to abolish the government of the Republic of Turkey or to prevent it, in part or in full, from fulfilling its duties"[30]) was related to an investigation on Gezi Park protests.
Related to Article 312 or the Gezi Park Trial as it is referred to in the press, a criminal indictment seeking life imprisonment for Kavala and 15 other people, including journalist Can Dündar and actor Memet Ali Alabora, was accepted on 4 March 2019 by the Istanbul 30th Heavy Penal Court.
[31] The indictment accuses the defendants of forming the mastermind behind the scenes of the Gezi Park protests, which is characterized as an "attempt to overthrow the government through violence" in this document.
[30][39] This arrest happened only one day before the ruling of the European Court of Human Rights about Kavala's pretrial detention demanding his release became final on 10 March.
French politician Daniel Cohn-Bendit, in a public letter to Osman Kavala on 29 March 2018, wrote, "I try to understand the reason behind your arrest, but I cannot apprehend it.
This ruling stated that there was no sufficient evidence to support the accusations against Kavala and that "the prosecution’s attitude could be considered such as to confirm the applicant’s assertion that the measures taken against him pursued an ulterior purpose, namely to reduce him to silence as an NGO activist and human-rights defender, to dissuade other persons from engaging in such activities and to paralyse civil society in the country."
[45] On 3 December 2021 Council of Europe (COE) says it will notify Turkey of its intention to launch "infringement proceedings" against the country over its failure to release philanthropist Osman Kavala.
[46] On 23 October 2021, the demand for Kavala's release was supported by ten embassies (Canada, Denmark, Finland, France, Germany, the Netherlands, New Zealand, Norway, Sweden, and United States), whose ambassadors were subsequently declared "persona non grata" in a statement by president Erdoğan.
[47][48] On 25 October, Erdogan backtracked on his initial threats to expel the ten ambassadors, stating that the diplomats had fulfilled their commitment to Article 41 of the Vienna Convention and that they would "be more careful in their statements.
"[49][50] British human rights activist and journalist, William Nicholas Gomes wrote to President Recep Tayyip Erdoğan to immediately and unconditionally release Osman Kavala.