According to the prosecution, 18 more soldiers are being sought.
Since the failed coup, Turkish authorities have arrested nearly 26,000 people accused of alleged ties to Gülen. Of these, around 9,000 have been imprisoned.
Fetullah Gülen died in October last year. He was close to Turkey's President Recep Tayyip Erdogan many years ago, but they later became enemies. Gülen fled to the USA in 1999 and never returned.
At the same time, prosecutors have filed a new indictment against Istanbul's imprisoned mayor Ekrem Imamoglu. In the latest indictment, he is accused of insulting two prosecutors during a court appearance in March.
Imamoglu is also the subject of several other investigations and charges. If he is convicted of the latest charge, he risks up to four years in prison.
Imamoglu has been seen as the main challenger to Erdogan for the presidency and his arrest in March triggered demonstrations across the country.
