Turkey's former army chief was arrested on Friday over an alleged plot to topple the government of Turkish Prime Minister Recep Tayyip Erdogan. General Ilker Basbug is accused of leading a terrorist organization.
Basbug was questioned for seven hours by Istanbul prosecutors and then sent to prison. Speaking to reporters as he was taken away, Basbug described the situation as "tragic comedy."
But Turkish political scientist Cengiz Aktar said the arrest represents a changing of the guard.
"It's a grand premiere. It has never before happened before in the republican history of this country since 1923. This man was in charge until a few years ago. It's a major development," said Aktar.
Led by influential officers, Turkey's military ousted four governments between 1960 and 1997.
Turkey's current Islamist-leaning government has shown contempt for the secular opposition.
Turkish authorities have detained more than 300 people, including journalists, academics and politicians, as part of a wide-reaching investigation into a secular network known as Ergenekon.
The Turkish army sees itself as appointed guardian of the secular state.
Basbug was allegedly involved in an Internet campaign to undermine the ruling AK party by publishing allegations of corruption. He is one of hundreds of people jailed or tried as part of the four-year-long probe into secular dissent.
Yasemin Congar, deputy editor of the Turkish newspaper Taraf, said it is right to weed out people bent on overthrowing the government.
"It's basically about digging out the dirt within the state. If this country's prosecutors manage to go to the end of this, Turkey will definitely be more democratic, definitely more secure and [a] more transparent country."
But criticism over the probe is growing. Critics say evidence against suspects is often thin.
In court, Basbug confronted accusations against him, saying that as chief of a 700,000-strong military, he would have used other methods rather than publishing Internet stories had he intended an overthrow.
Retired Brigadier General Haldun Solmazturk said former and current military men are being targeted for expressing opinions against the government.
"Turkish democracy is reversing. It's going back. It's not advancing," said Solmazturk.
At least 58 military men are in jail. So far, none have been convicted.
Turkish political scientist Aktar of Istanbul's Bahcesehir University said the credibility of the Ergenekon probe is increasingly in doubt.
"Judging by European and international standards, these trials are not fair. As long as there is no result to these ongoing custodies and trials, the entire Ergenekon case actually weakens," said Aktar.
If convicted, Basbug and others face decades in jail.