ByLock is said to have been used by members of the Fetullah Terrorist Organization (FETO), which the government has said was behind the attempted takeover, which martyred 241 people and wounded nearly 2,200 others.
The app is believed to have been cracked by Turkish security agencies before the coup, prompting the plotters to switch to the WhatsApp messaging service but not before tens of thousands of FETO suspects had been identified.
Turkey accuses FETO, which is led by U.S.-based Fetullah Gulen, of organizing the defeated coup as well as a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police, and judiciary.
More than 3,400 FETO-linked judges and prosecutors have so far been discharged by the board following the bid.
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