CAIRO — An Egyptian appeals court on Sunday overturned the conviction and life sentence of former president Hosni Mubarak for directing the killing of hundreds of protesters, a ruling that could prolong a politically fraught legal battle over the fate of the dictator two years after his ouster.
The court ordered a new trial for Mubarak and his former security chief, Habib el-Adly, who was convicted and sentenced to life in prison on the same charges.
Judge Ahmed Ali Abdel-Rahman also ordered the re- trial of six of Adly’s top aides, who were acquitted in the same trial. Five of them were found not guilty of involvement in the killing of the protesters, while one was acquitted of ‘‘gross negligence.’’
Mubarak, 84, is being held in a military hospital and will remain in custody while under investigation on charges in an unrelated case. The former president was reported to have been close to death last year, but the state of his health is unknown.
The appeals court did not immediately disclose the reasoning for its decision, but early reports suggested that it had found procedural problems in the conduct of the original hearings. No date has been set for the retrials.
In an interview with state media, Farid El-Deeb, a lawyer for Mubarak, said that ordering a new trial for the same crimes merely because the prosecution failed to produce any evidence of Mubarak’s direct involvement would be impermissible double jeopardy.
The judge who handed down the original verdict said at the time that he was convicting Mubarak on the principle of presidential responsibility even though he had seen no evidence that Mubarak had personally ordered or directed the killings.
More than 800 civilians were killed during the three weeks of protests that ended Mubarak’s 30-year rule.
Although expected, Sunday’s appeals court decision may also put the issue of retribution for Mubarak and his inner circle back in the news just as a campaign begins for new parliamentary elections, which are scheduled for April.
The decision may bolster the prospects of the Islamist party of President Mohammed Morsi, who campaigned for president last year on a pledge to seek a retrial of Mubarak, capitalizing on anger over the weak conviction shortly after it was released. Even as his opponents had begun collaborating with former members of Mubarak’s old party, Morsi has made legal action against leaders of the former government a priority, sometimes suggesting that corrupt former colleagues of Mubarak were behind a conspiracy to disrupt the transition to democracy.
A ruling that overturned Mubarak’s conviction had been considered likely since his conviction last year. The trial’s presiding judge criticized the prosecution’s case, saying it lacked concrete evidence and that nothing in what was presented to the court proved that the protesters were killed by the police.
Perhaps in anticipation of the appeals court decision, prosecutors on Saturday ordered that Mubarak be detained for an additional period because of a new investigation they had started into personal gifts he received from Al Ahram, the state media organization that publishes a newspaper of the same name. Now under new management, Al Ahram reported Saturday that Mubarak was under questioning about gifts including gold pens, designer neckties, leather bags, shoes, gold jewelry, and expensive watches that the media organization gave him between 2006 and 2011 as demonstrations of loyalty.
Earlier this month, a presidential fact-finding committee presented a report to Morsi that accused Mubarak of having far more direct awareness of the violence against the protesters than previously disclosed.
The website of the Information Ministry last week, citing unnamed sources familiar with the commission’s conclusions, reported that it found that Mubarak had watched the brutal tactics of his security forces in the streets over a special television monitor in his office and also received ‘‘firsthand reports.’’