Turkish officials have indicated that Pennsylvania-based cleric Fethullah Gülen was connected to the fatal shooting. He denied claims on Thursday.
President Recep Tayyip Erdoğan has accused Fethullah Gülen, the secretive cleric who lives in Pennsylvania, of plotting the coup.
Fethullah Gulen, an archrival of the Turkish president, has been living in the U.S. for decades and is now being sued for allegedly persecuting his own rivals.
The movement associated with Turkey's Fethullah Gülen is making inroads in U.S. politics.