Turkish authorities detained two suspects in Istanbul and Muğla on Friday as part of an investigation into the current activities of the Gülenist Terror Group (FETÖ), judicial sources said.

The Istanbul Chief Public Prosecutor’s Office ordered searches and seizures at three addresses in Istanbul and one in the southwestern province of Muğla as investigators sought to uncover the group’s ongoing activities.

Esma Batmaz, daughter of Kemal Batmaz, a senior FETÖ figure detained at Akıncı Air Base following the failed July 15, 2016 coup attempt, was detained in Istanbul.

Hilal Köseoğlu, whose father Bilal Köseoğlu was dismissed by decree while serving as a judge and prosecutor at the Ankara Courthouse, was detained in Muğla. Her father is currently imprisoned in Muğla.

Authorities seized a large amount of digital material during the searches, with examinations continuing.

The operations came as Justice Minister Akın Gürlek said Thursday that investigators examining the 2009 death of politician Muhsin Yazıcıoğlu had uncovered evidence pointing to links with FETÖ.

Yazıcıoğlu, founder and leader of the Great Unity Party, and five others were killed when their helicopter crashed in Kahramanmaraş in March 2009.

Gürlek remarked that investigators had identified connections between the helicopter’s pilot and senior FETÖ figures, including Adil Öksüz and Kemal Batmaz.

The minister noted investigators had found that a meeting involving FETÖ’s covert operatives and the helicopter pilot was held in the eastern province of Elazığ several days before Yazıcıoğlu’s death. He said senior FETÖ figures Öksüz and Batmaz attended the meeting, adding that Öksüz left Türkiye a day before Yazıcıoğlu’s death.

"There are actions with very strong links to FETÖ,” Gürlek stressed, adding that authorities would pursue the case regardless of where the evidence leads.

Separately, Gürlek stated an investigation into an alleged criminal organization led by Alihan Kuriş was continuing after a third wave of operations.

He underlined that investigators were examining allegations including money laundering, fraud and the transfer of funds abroad, as well as the 2016 death of former Transport Minister Arif Ahmet Denizolgun.

Preliminary findings further indicated "serious signs” that Denizolgun’s death may have been suspicious, citing bruising around the neck, allegations of strangulation and claims that medical teams were notified late, the minister noted.

A forensic report on Denizolgun’s death is pending and could determine the next steps in the investigation, he added.