"If there's a nationwide movement against this, you'll (also) have a nationwide movement for it," Trager said.
After he was elected, Morsy took legislative control from the Supreme Council of the Armed Forces, which had ruled after Mubarak was deposed. Earlier, the council dissolved parliament's lower house, saying parliamentary elections that began in November 2011 were unconstitutional. Morsy indicated in June he would call back parliament, but Egypt's high administrative court upheld the dissolution.
Mubarak and his former Interior Minister Habib El Adly were convicted and sentenced in June to life in prison on charges relating to the deaths of hundreds of protesters after a 10-month trial, while six former government aides were acquitted. Some Egyptians protested the sentences and acquittals.
Morsy, who still was running for office, said at the time that he would initiate new investigations if elected.
About 840 people died and more than 6,000 others were injured in last year's 18-day uprising, according to Amnesty International.