Security forces captured fifteen suspects on Tuesday in a string of operations against the Gülenist Terror Group (FETÖ). Operations against the terrorist group behind the July 15, 2016, coup attempt have become almost routine since the attempt escalated inquiry into the group’s activities.

In the western province of Afyonkarahisar, prosecutors issued arrest warrants for eight suspects. All were detained in operations in Afyonkarahisar and five other provinces. Suspects were accused of working as “secret imams” for FETÖ, a name given to the group’s civilian handlers for its infiltrators in the army, judiciary, law enforcement or any other public agency. Captured suspects were handlers for cadets at a police school in Afyonkarahisar, according to authorities. They served as FETÖ’s “imams” for cadets loyal to the group between 2008 and 2016, investigators say. The detainees were teachers, engineers and academics and some were users of Bylock, an encrypted messaging app exclusively used by FETÖ, according to investigators.

ByLock was discovered during criminal inquiries into the terrorist group, whose illegal activities have been under the spotlight since two coup attempts in 2013. The National Intelligence Organization (MIT) uncovered the messaging app apparently programmed or modified for the exclusive use of the group's members. A group of intelligence officers has been accused of controlling the private app used to deliver FETÖ leader Fethullah Gülen's messages to his followers, as well as to instruct the group's members on how to carry out plots against anti-Gülenists.

Four fugitive FETÖ suspects convicted of membership in the terrorist group and sentenced to seven years and six months in prison in absentia, were captured in another operation in the central province of Konya. Suspects were tried following the coup attempt in 2016 in a mass trial of the terrorist group’s network in the province.

Elsewhere, security forces detained three FETÖ suspects in a military-controlled zone near the Greek border in the northwestern province of Edirne. Suspects were trying to sneak into Greece when they were detected in an area in Ipsala district. On Monday, another two suspects linked to the group were detained in the Uzunköprü district of Edirne as they tried to cross into Greece. One was detained while the other suspect was released with judiciary control. Greece has been the favorite gateway for suspects linked to the group, though most prefer land routes in Turkey's northwest. The European country attracted more FETÖ fugitives after it refused to extradite soldiers involved in the 2016 coup attempt to Turkey after they hijacked a military helicopter and took shelter in Greece. Over 8,000 FETÖ members have crossed into Greece in the past three years, according to authorities. Ankara has criticized the country for ignoring its calls for international cooperation against the terrorist group.