Public Prosecutor Hisham Barakat was killed during a car bombing in eastern Cairo in June 2015, leaving some of his guards injured as well, Xinhua news agency reported.
According to the investigation of the Egyptian homeland security, the defendants were in contact with the Hamas movement, and they plotted together with the Brotherhood leading members to target a number of state figures to cause disorder and instability in the country.
The prosecution on Sunday said the defendants received training in Hamas military camps in the Gaza Strip, where they were provided with the necessary explosive devices for the bombing.
Hamas has repeatedly denied any involvement in Barakat’s assassination, and a delegation of Hamas had recently visited Cairo and made favourable statements in a bid to refresh ties.
Barakat referred thousands of supporters of ousted Islamist president Mohamed Morsi to trial over various charges related to violence and terrorism.