He was acquitted by an Egyptian military court and will be released Tuesday, said attorney Nizar Ghorab.
Mohamed al-Zawahiri was imprisoned in 1999 after being detained and extradited from the United Arab Emirates on allegations that he was linked to the 1981 assassination of Egyptian President Anwar Sadat. Al-Zawahiri was acquitted on the assassination charges but later was accused of conspiring against the Egyptian government.
He was sentenced to death, but then appealed the ruling.
Last year, Egypt's interim government released him along with scores of other political prisoners after a general pardon was issued by the Supreme Council of the Armed Forces, which ruled the country after the ouster of President Hosni Mubarak. But al-Zawahiri was arrested again shortly after. Read More