Turkish police detained 12 people, including two prominent academics, on Friday as part of an investigation into leading rights activist and businessman Osman Kavala and his cultural organization, state media said.

Kavala was jailed pending trial a year ago, accused of seeking to overthrow the government as part of an investigation into the network which Ankara accuses of carrying out a 2016 failed coup.

Human rights groups and European Parliament members have repeatedly called for his release and an indictment against him has not yet been issued.

The two academics were named as 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.

State-owned Anadolu news agency said Istanbul prosecutors had in total sought the arrest of 20 suspects and police had carried out simultaneous raids at various addresses.

Among the detainees were staff of Kavala’s Anadolu Kultur organization, which is involved in promoting culture and rights, including board members Yigit Ekmekci and Hakan Altinay. It was not immediately clear what they were accused of.

In a statement marking one year since he was remanded in custody, Amnesty International and Human Rights Watch renewed calls at the end of October for Kavala’s immediate and unconditional release.

Since the attempted putsch in July 2016, Turkey has jailed 77,000 people as they face trial, as well as suspending or dismissing 150,000 civil servants and military personnel and shutting down dozens of media outlets.

Police still frequently carry out operations targeting the network of U.S.-based cleric Fethullah Gulen, who Ankara accuses of orchestrating the July 2016 failed putsch.

Anadolu said on Friday that prosecutors issued an order for the arrest of 188 people, including 100 former air force personnel, over links to Gulen’s network. So far 86 suspects have been detained in the operation.