Turkish security forces nabbed 35 out of 51 suspects in nationwide operations again the Gülenist Terror Group (FETÖ) Friday.

The arrests were made in 19 provinces as a result of warrants issued by the Chief Prosecutor’s Office in the capital Ankara. A manhunt is underway for the remaining suspects.

All suspects are charged with being part of a secret network of the terrorist group within the Turkish Armed Forces (TSK). They were identified through their contact with each other via payphones in public locations like grocery stores, to avoid detection. Suspects include both former and active-duty soldiers and their civilian handlers for the terrorist group. Four among them were former military cadets expelled from military schools on suspicion of links to FETÖ.

FETÖ faced heightened scrutiny after the July 15, 2016 coup attempt, the work of its infiltrators in the military, from generals to lieutenants. Although it posed as a charity group with religious undertones, FETÖ maintained deep secrecy while working to orchestrate plots against the government, multiple investigations showed.

The terrorist group is also accused of using its infiltrators in the police and the judiciary to launch two other coup attempts on Dec. 17 and Dec. 25, 2013, under the guise of graft probes, in addition to sham trials launched against its adversaries using illegal or fake evidence and trumped-up charges.

Tens of thousands of people were detained or arrested for their links to FETÖ and for playing an active role in the coup attempt since 2016. The army largely managed to weed out infiltrators of the group in its ranks but the group’s tactics to disguise its infiltrators worry the authorities. Authorities work to identify secret members of the group in hundreds of investigations launched across the country.

Interior Minister Süleyman Soylu said Thursday that security forces seized 2.6 million digital and physical “materials” from FETÖ that serve as evidence of the group’s activities, but there are still 85,000 pieces of such evidence that needs to be examined among them, citing the difficulty of proper examination of computers, cellphones and other devices containing evidence, “which sometimes takes more than one year.”