The suspects were rounded up after prosecutors in Adana issued arrest warrants for 13 active-duty soldiers as part of an investigation into the group's secret structure in the Turkish Armed Forces.
Since May 2016, the FETO organization has been classified as a terrorist organization by Turkey under the assigned names Fethullahist Terrorist Organization and Parallel State Structure.
After the failed coup attempt in 2016, the government of Turkey blamed the group for the coup and authorities have arrested thousands of soldiers and judges who have links to the organization.