Specially authoritzed İstanbul Public Prosecutor Hüseyin Ayar interrogated the two colonels on Tuesday in İstanbul courthouse in Beşiktaş and referred them to court for arrest.
The 15th İstanbul High Criminal Court arrested Col. Berker Emre Tok on coup charges, while releasing the other colonel pending trial.
Sledgehammer is a suspected coup plot believed to have been devised in 2003 with the aim to unseat the Justice and Development Party (AK Party) government through violent acts. According to the Sledgehammer plan, the military was to systematically foment chaos in society through violent acts, among which were planned bomb attacks on the Fatih and Beyazıt mosques in İstanbul.
The plot allegedly sought to undermine the government to lay the groundwork for a coup d’état. The military, which has overthrown three governments since 1960 and pressured a conservative government to step down in 1997, has denied there was such a plan.