Dozens of journalists are under investigation for possible links to the attempted July 15 coup in Turkey.
Among the 42 reporters is Nazli Ilicak, a prominent critic of the current regime.
It is not clear if any of those being investigated have been detained.
All the journalists being probed have links to media owned by Fethullah Gulen, a U.S.-based cleric who was accused by Turkish President Recep Tayyip Erdogan, of organising last week coup.
Ilicak worked for Sabah, a newspaper with government ties, until the end of 2013, when she demanded that several ministers from the mildly Islamic-rooted ruling Justice and Development Party (AKP) step down amid corruption scandal.
AKP members said that the corruption allegations were a conspiracy organised by Gulen, who was once a close ally of Erdogan, but has in recent years been accused of multiple plots by the government.
Thousands of Gulenists have been cleared from government jobs in recent years, a process that has escalated since the coup.
Ilicak has also worked for the newspaper Bugun, which was considered to be associated with Gulen.
The government took over Bugun last year, changed its editorial direction and then shut it down, one of several media outlets that have come under fire in Turkey in recent years.
