Mohammad el-Zawahiri was arrested in 2013 and accused of joining a terrorist group linked to al-Qaeda that targets security forces and minority Christians as well as planning attacks following the army's overthrow of Islamist president Mohammad Morsi after massive protests against his rule.
In October, 2015, al-Zawahiri was acquitted of setting up a terrorist organisation in what was known as the al-Zawahiri cell case.
Seventeen other defendants were charged in the same case, 10 of them were sentenced to death in 2015.