Ahmet Altan, a prominent novelist and former Editor-in-Chief of Taraf newspaper and his brother, Mehmet Altan were being investigated for comments they made on a talk show aired on Can Erzincan TV channel on July 14, on the eve of the coup attempt, The Hurriyet daily news reported.
Among those arrested earlier is Nazli Ilicak, veteran journalist and writer, who also appeared on the same talk show with the Altan brothers. Nazli Ilicak was arrested on July 29 on terrorism charges in the probe into the failed coup.
Ilicak's testimony will also be sought as part of the probe, according to the report.
Ahmet Altan is also on trial along with his colleagues for "leaking state secrets" for stories on an alleged coup plan by the Turkish military.
Meanwhile, Hurriyet reporter Arda Akin, who had been arrested for alleged links to US based cleric Fethullah Gulen, accused of masterminding the July 15 coup attempt, was released pending trial on September 9.
Over 100 journalists have been arrested since July 15 in the probe against followers of Gulen.
