A Kirklareli man, identified as M.B., was detained while he was visiting his elder brother, Ş.B., who has been under arrest over links to the Gülen movement in a prison in the province, on Aug 26.
According to Turkish media, an arrest warrant had been earlier issued against the visitor M.B. on accusation of membership to the movement.
M.B. was rounded up by the law enforcement and later put in pre-trial arrest by the court in charge.
The government has already detained more than 120,000 people and arrested some 55,000 over links to the movement so far.
The Gülen movement denies involvement in the failed coup.