Two former prosecutors and one judge, who are linked to the investigation into FETÖ plots to imprison the group's critics and summon of the National Intelligence Directorate (MİT) chief Hakan Fidan, have been detained on Friday in Istanbul.

Former judge Dursun Ali Gündoğdu and prosecutors Sadrettin Sarıkaya and Adnan Çimen were captured by Turkish security forces in Istanbul's Başakşehir district. Security officials also seized fake IDs during the raids.

A few years ago, Sarıkaya summoned the National Intelligence Directorate (MİT) chief Hakan Fidan for a testimony, apparently for his arrest in a controversial case. Fidan did not heed the call.

Fidan's phone call with then-Prime Minister Recep Tayyip Erdoğan turned this around, as Erdoğan strictly prevented Fidan from testifying before Sarıkaya. Many in Turkey have speculated that Sarıkaya intended to summon Erdoğan after the MİT head was questioned.

The other two suspects were involved in trial of Selam Tevhid, an imaginary group created by FETÖ-linked prosecutors and police officers to imprison the terror cult's critics on forged evidence and trumped-up charges.

FETÖ, which posed as a religious group, is implicated in a string of cases, ranging from illegal wiretapping to the recent coup attempt. Most of its senior leaders remain at large and abroad, including its leader Fetullah Gülen who lives in a Pennsylvania retreat while he faces multiple life sentences in trials in Turkey.