The High Council of Judges and Prosecutors (HSYK) launched an inquiry into prosecutors involved in the "Sledgehammer," or Balyoz coup plot trial. Turkey's Vatan daily reported that the inquiry came at a time when there is an investigation into allegations that defendants were victims of fabricated evidence.

Defendants have long complained that they were victims of a plot against the Turkish Armed Forces and charges of an alleged coup plot was based on fabricated and forged evidence. They had implied that a "parallel structure," a secret organization within the judiciary and police affiliated with the controversial Gülen Movement, was behind a plot against them.

It is the first time that the top body overseeing the judiciary launched an inquiry into the matter. Eight prosecutors are among those facing investigation. The Vatan daily reported that a chief inspector from HSYK in charge of the inquiry would announce his report in the coming days on whether the prosecutors would be charged.

In September 2012, the Turkish Supreme Court had sentenced the defendants to six to 20 years imprisonment. The trial of 236 defendants started from scratch last year after a court ordered a retrial following a higher court's verdict that cited the rights of defendants were violated and evidence against them might have been tampered with.

The coup plot, first published by a Turkish daily in 2010, called for inciting chaos in Turkey to pave the way for military intervention. According to the alleged plan, the military would incite chaos through violence such as bombing mosques in Istanbul and deliberately downing a warplane over the Aegean Sea and make it look like the work of the Greek army.

Defendants include Turkish Armed Forces' former First Army Commander, Çetin Doğan, former Air Forces Commander, Halil İbrahim Fırtına, former Naval Forces Commander, Özden Örnek, former Special Forces Commander and opposition Nationalist Movement Party (MHP) lawmaker, Engin Alan and other top military officers.

All defendants were freed after the Constitutional Court's verdict in June. Defendants had claimed that all documents implicating them in the case were forged. One of the most striking allegations about the forged evidence is that an allegedly authentic Microsoft Word document detailing the coup plan conceived in 2003 was written in a 2007 version of the word processing software.

Some defendants claimed the police planted the documents on their computers without their knowledge. Defendants also claimed police or "people plotting against them" hacked into their computers and secretly installed those documents in their hard drives.

The Gülen Movement is accused of being a major force in a series of trials targeting military officers through "forged" evidence, according to their critics.