Turkish police detained 25 suspects in an operation targeting the Gülenist Terror Group (FETÖ) in Istanbul, authorities announced Tuesday, as part of an ongoing crackdown on the network accused of orchestrating the 2016 failed coup.

The Istanbul Chief Public Prosecutor’s Office said the suspects were identified through an investigation into alleged use of the encrypted messaging app ByLock, which authorities consider a key communication tool of the group.

Among those detained are seven active public employees and four dismissed from public service.

Investigators also found that some suspects had records of so-called payphone contacts, had previously stayed in properties linked to the terrorist group, held accounts at Bank Asya or were registered with companies affiliated with the group, officials said.

All 25 suspects were taken into custody during coordinated raids carried out by Istanbul police.

In a separate operation on Monday, authorities in Kayseri captured a fugitive former noncommissioned officer sentenced to six years and three months in prison for FETÖ membership. He was later transferred to prison following processing.

The terrorist group orchestrated the defeated coup of July 15, 2016, in Türkiye, in which 252 people were killed, and 2,734 were wounded. Ankara also accuses FETÖ of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.

Türkiye has targeted its active members and sleeper cells nonstop, and its influence has been much reduced since 2016.