Warrants were issued to round up 23 teachers who used to work for the schools that the government shut down over ties to the Gulen movement after the July 15, 2016 coup attempt.

The teachers are accused of using the smart phone application ByLock, which according to prosecutors was a top communication tool among members of the movement, accused by the government of masterminding the failed coup.

The detention warrants were issued by the Ankara’s Public Prosecutor’s Office early on Friday.

Tens of thousands of civil servants have either been dismissed or arrested for using the application. Critics say the use of a technological application is not a criminal activity nor is it evidence of membership in a terrorist organization.

Turkey survived a military coup attempt on July 15 that killed over 240 people and wounded more than a thousand others. Immediately after the putsch, the government along with President Recep Tayyip Erdoğan pinned the blame on the Gülen movement, inspired by Gülen. The movement denies involvement in the coup attempt.

At least 3,008 schools, universities and student dormitories have been shut down over ties to the movement since the summer of 2016.