Turkish police on Tuesday arrested 75 suspects for their alleged links to Fetullah Terrorist Organization (FETO), the group behind the 2016 defeated coup attempt, security sources said.

The arrests first came after prosecutors in Istanbul issued warrants for 54 suspects.

The police conducted simultaneous raids across the country, and arrested 28 suspects on charges of using the terror group’s encrypted smartphone messaging app, ByLock.

Read more: Turkey: 75 FETO-linked terror suspects arrested