Thousands of people accused of taking part in an attempted coup have been traced via a messaging app, a senior Turkish official has disclosed.
Having been tracked down by the authorities, ByLock had been abandoned by members of the dissident Gulen movement before the coup attempt.
But some 40,000 undercover operatives, including 600 ranking military personnel, had already been identified.
Experts stated that ByLock appeared to be the work of amateur developers.
The Gulenists are followers of exiled Muslim cleric Fethullah Gulen, who now lives in the United States.
Turkish President Recep Tayyip Erdogan has blamed army officers within the group for orchestrating the coup attempt.
Mr Gulen denies any connection to the plot.
The Turkish official said: “The ByLock data made it possible for us to map their network – at least a large part of it.
“What I can say is that a large number of people identified via ByLock were directly involved in the coup attempt.”