Turkish Prime Minister Binali Yıldırım’s chief advisor was reportedly detained on Saturday in Ankara as part of an investigation into Turkey’s Gülen group, which the government accuses of masterminding a failed coup attempt in Turkey on July 15, 2016.

According to the state-run Anadolu news agency, chief advisor Birol Erdem and his wife Gülümser Erdem were detained in Ankara for alleged membership in the Gülen group as part of the same investigation launched by the Ankara Chief Public Prosecutor’s Office.

A former member of the Supreme Board of Judges and Prosecutors (HSYK), Birol Erdem served as Justice Ministry undersecretary between 2011-2014 before being appointed chief advisor to the prime minister.

Turkey survived a military coup attempt on July 15 that killed over 240 people and wounded more than a thousand others. Immediately after the putsch, the Justice and Development Party (AKP) government along with President Recep Tayyip Erdoğan pinned the blame on the Gülen group.

The group denies any involvement.