Unlike the initial lenience shown by the government to the rebels following the 1962 coup attempt, where they were granted a full pardon, a harsher approach was taken instead this time.
[5][6] On 22 March 1963, Ex-President Celal Bayar was temporarily released from Kayseri prison, and was warmly received by large crowds when he arrived in Ankara, to the anger and consternation of those who had supported the 1960 coup.
[7][8][9] In November 1960, fourteen radical officers had been removed from the military National Unity Committee that had seized power in the coup of the previous May.
These attempts at unity ended in abject failure however, primarily due to Aydemir's insistence on primary leadership which caused frustrations during negotiations with the other groups.
[10] Upon hearing the results of the Pierre Loti meeting, Colonel Aydemir decided to act independently and launch the coup attempt without further delay, mobilizing the Tentacle System by the evening of May 20.
The colonel and his chief collaborators, in their old uniforms, entered the Turkish Military Academy and misled the cadets into joining, claiming the entire armed forces were rising up.
By midnight, the rebels had seized control of the radio station, announcing that Aydemir had taken over the government on behalf of the army, dissolving parliament and abolishing political parties.
Lieutenant-Colonel Ali Elverdi, a loyalist, managed to infiltrate into the studio and broadcast a denial of the colonel's claims, calling for loyal forces to rally.
The proceedings, conducted with military discipline, were criticized by the defendants, who were limited to only one defense attorney each, leading them to challenge the court's legitimacy.
Aydemir and his associates, rather than mounting a defense, instead admitted and expressed pride in their actions, attempting unsuccessfully to implicate top officials into the coup.
[14] Alparslan Türkeş, who opposed Colonel Aydemir's plans, was arrested but later acquitted in the Mamak trials for his role in leaking the plot to the government.