Turkish police detained 12 people on November 16th as part of an investigation into prominent civil society leader and sponsor of Amnesty International Osman Kavala and his cultural organisation, state media said.
Accused of seeking to topple the government during the 2016 failed coup, Kavala was jailed pending trial a year ago.
Without publicly declaring the charges on which arrest warrants were issued, Turkish authorities detained staff at Kavala's Anadolu Kultur organisation, which is involved in promoting culture and rights; board members Yigit Ekmekci and Hakan Altinay were among those held.
The arrests also included two prominent academics, Turgut Tarhanli, Dean of the law faculty at Istanbul Bilgi University, and maths professor Betul Tanbay of Bogazici University, who was elected this year as vice president of the European Mathematical Society.
Human rights groups and European Parliament members have repeatedly called for Kavala’s release and an indictment against him has not yet been issued.
Despite criticism from many countries, President Erdogan has led a harsh crackdown on dissent, jailing some 77,000 people, as well as suspending or dismissing 150,000 civil servants and military personnel and shutting down dozens of media outlets.