Responding to a request from the court trying defendants over the 2007 murder of prominent Turkish-Armenian journalist Hrant Dink, police acknowledged that 18 defendants in the case used ByLock. ByLock is an encrypted messaging app used by members of the Gülenist Terror Group (FETÖ) and authorities believe it was created or at least modified by the group to cover up their activities, Daily Sabah reports.

Dink, the editor-in-chief of the Armenian Agos weekly, was assassinated outside his Istanbul office on Jan. 19, 2007, in a murder initially attributed to nationalists disturbed by his outspokenness on the Armenian genocide, a thorny issue for Turkey, and especially nationalists. Ogün Samast, a teenager, was captured and sentenced to 23 years in prison for the daylight murder, but further inquiry found several public and police officials linked to FETÖ tried to cover up the case.

FETÖ, which is also blamed for last year's deadly coup attempt, used the murder to "incite chaos" in Turkey, according to prosecutors. FETÖ supporters had blamed several prominent figures from military officers to academics of having a role in the murder and tried to tie it to Ergenekon, a gang concocted by FETÖ-linked prosecutors to imprison its critics. The first trial for the murder ended in 2012, only trying 19 defendants. At the time, an Istanbul court ruled in favor of the prison sentences for Samast and his friends, including a police informant. A higher court had thrown out the terrorism charges for the suspects, saying Samast and the others were merely members of a criminal gang.

A new investigation years later turned the spotlight on the role of police chiefs and intelligence officials accused of covering up intelligence reports on the murder plot and evidence of possible negligence by the prosecutors and judges handling the murder case, as it was determined that the prosecutors and judges were linked to FETÖ.

Ramazan Akyürek and Ali Fuat Yılmazer, who were senior officials in police intelligence at the time of Dink's murder, face life imprisonment on charges of homicide and terrorism as well as forgery and destroying official documents while other public officials face shorter prison terms for negligence and abuse of duty for their role in the cover-up.

Although the defendants' FETÖ links have long been acknowledged by prosecutors, it is the first solid evidence of the defendants' ties to the terrorist group, Daily Sabah says. Recently, the Supreme Court had ruled that the usage of ByLock was sufficient evidence to use to prove membership in the group.

Anadolu Agency (AA) reported that among the ByLock users in the case is Adem Yavuz Arslan, a fugitive FETÖ member who wrote a book about the murder, fugitive FETÖ-linked prosecutor Zekeriya Öz and former police Chiefs Metin Canbay and Yakup Kurtaran. Ercan Gün, a journalist tried in the case, also used ByLock, according to the police.