Turkish police on Friday arrested 40 former police over alleged links to the Fetullah Terrorist Organization (FETO), the group behind the 2016 defeated coup attempt, security sources said.

The expelled police members were arrested in the Konya, Gaziantep, Kayseri, Adiyaman, Adana, Trabzon, Yozgat, Bursa provinces and in the capital Ankara.

A total of 50 suspects, including four police chiefs, were sought as part of a probe into FETO’s clandestine network in the police forces.

The police continue the hunt for the remaining suspects.

FETO and its U.S.-based leader Fetullah Gulen orchestrated the defeated coup of July 15, 2016, which

Read more: Turkey: Police arrest 40 FETO-linked terror suspects