At least 30 people including teachers, businessmen, and public servants in Tekirdağ province were detained over their alleged use of ByLock mobile app on Saturday.
Turkish authorities believe using ByLock is a sign of being a Gülen follower as they see the mobile phone application as the top communication tool among the group. Then government accuses the movement of masterminding the July 15, 2016 coup attempt while the latter denies involvement.
Tekirdag public prosecutors issued warrants to detain 42 people and police have been able to round up 30 of them as of early Saturday.
More than 120,000 people have already been taken under custody, of which some 55,000 were put in pre-trial arrest.