The three judges presiding in Muslim Brotherhood chief Mohamed Badie's trial withdrew from the proceedings Tuesday for "reasons of conscience," just days before Egypt's ousted Islamist president Mohamed Morsi goes on trial.
Badie and his two deputies, Khairat al-Shater and Rashad al-Bayoumi, face charges related to the deaths of protesters who stormed the Brotherhood's Cairo headquarters on June 30 this year.
"The judges are retiring from this case for reasons of conscience and the accused must remain in detention," head judge Mohammed Fahmy al-Qarmuty told the court at the start of the session, without elaborating.
It was not immediately clear what prompted the judges to step down and it is expected that new judges will be appointed to hear the case.
Defense lawyer Mohamed Damaty insisted "there is no evidence at all in the case."
He told AFP that the authorities wanted to keep the accused behind bars on a preventative basis "because they know very well that the proceedings are political."
The judges' decision to step down will "prolong the process," he added.
A total of 32 other defendants are being prosecuted along with Badie, Shater and Bayoumi. None of the 35 were in the court on Tuesday, when the second session of their trial began.
An official told AFP that the defendants were not brought to the court for security reasons.
Badie, Shater and Bayoumi face charges of inciting the murders of nine protesters on June 30. If found guilty, they face the death penalty.