A former football player for Fenerbahçe was arrested Friday over suspected links to the Gülenist Terror Group (FETÖ).

The arrest came after Istanbul prosecutors issued a warrant for Zafer Biryol when he was allegedly found to be using ByLock, an encrypted smartphone-messaging app used by FETÖ members. Biryol was also accused of being a member of a terrorist organization.

In his career spanning the early 2000s, Biryol played for several football teams, including Göztepe, Konyaspor, Fenerbahçe, Çaykur Rizespor, Bursaspor and Mersin Idmanyurdu.

Media outlets reported that he was arrested as part of a probe into the terrorist group's supporters in Turkish football. Bekir İrtegün, another former Fenerbahçe player, was briefly detained in July for links to FETÖ. Turkish media reports claim İrtegün was released when he "confessed" the group's infiltrators in Turkish football clubs. Ömer Çatkıç, another former player detained in the same case, remains jailed for links to the group.

Separately, in an Istanbul-based operation spanning five provinces, 22 FETÖ suspects were detained. As part of the investigation launched by Istanbul prosecutors, the operation was launched to arrest 42 former and current employees of Marmara University. The suspects, including 24 currently working at the university, were accused of using the ByLock app.

Meanwhile in the northwestern province of Edirne, four FETÖ suspects, including a woman, were arrested while trying to enter Greece illegally, according to a military source, who asked not to be named due to restrictions on talking to the media. Two of the four suspects were also accused of using ByLock. FETÖ suspects have been trying to leave the country to avoid arrest.