The Ankara Deputy Chief Public Prosecutor's Office had said several detention warrants were issued, including two for lieutenant generals. Police also raided retired Brig. Gen. Kenan Deniz's house.
The suspects are all accused of playing a major role in the Feb. 28 coup, when the military forced a coalition government led by a now-defunct conservative party, the Welfare Party (RP), out of power.
Thirty-nine people were earlier arrested in the first three operations in the Feb. 28 investigation. Those sent to jail include retired Gen. Çevik Bir, who is known to have played a major role in the 1997 coup, and retired Gen. Erol Özkasnak, the secretary-general of the General Staff at the time. Özkasnak is known to have played a major role in the coup generals' communication with the media in order to put pressure on the government to resign.
Reportedly at the heart of the Feb. 28 investigation are the actions of the West Study Group (BÇG), which was established within the military to categorize politicians, intellectuals, soldiers and bureaucrats according to their religious and ideological backgrounds before and after the coup. Bir, the deputy chief of General Staff at the time, was the head of the BÇG.
The Feb. 28 coup introduced a series of harsh restrictions on religious life, with an unofficial but widely practiced ban on the use of the Islamic headscarf. The military was also purged of members with suspected ties to religious groups or even officers who were simply observant Muslims. In addition, a number of newspapers were closed down after the coup based on an MGK decision that called for closer monitoring of media outlets.