Sogut, a former employee of the Turkish Information and Communication Technologies Authority (ICTA), is also considered to be a senior member of FETO, the media reported.
The suspect was arrested in Ankara on Thursday after the investigation into the assassination found that he was a user of the ByLock messenger that was used by the organizers of the 2016 failed coup attempt in Turkey, according to the agency.
On Monday, Ankara issued an arrest warrant for Islamic cleric Fethullah Gulen along with seven members of his movement — referred to by Ankara as the Fethullah Terrorist Organization (FETO) — in connection with the assassination.
Karlov was shot on December 19, 2016 by an off-duty Turkish police officer named Mevlut Mert Altintas at the opening of an art gallery exhibition called "Russia from Kaliningrad to Kamchatka through the eyes of a traveler" in Ankara. The attacker was killed at the scene by the police. Though the investigation is still ongoing, Turkey has repeatedly voiced suspicions that the Gulen movement, accused by the authorities of masterminding the failed coup attempt, is linked to the ambassador's assassination.