Egypt's court of cassation has refused an appeal by prosecutors over the "Camel Battle" trial.In October, a court acquitted 24 loyalists of deposed president Hosni Mubarak who had been accused of organising an attack in which assailants on horses and camels charged into crowds of anti-regime protesters on February 2, 2011.
The 24 were found innocent on charges of manslaughter and attempted murder.
The court did not immediatly release its reasoning for the appeal refusal.
The mounted attack, which included whip-wielding riders, became a symbol of the revolution and led to street clashes.
"The court has made this final decision on the fate of the 24 defendants who were accused of conspiring to kill protesters in that infamous incident," said Al Jazeera's Rawyeh Rageh, reporting from Cairo.
The scenes were televised around the world at the height of the uprising.
"These defendants were acquitted last year, sending shockwaves into the Egyptian community," our correspondent said.
"That has been confirmed today, with the court initially saying that there was not any 'sufficient evidence' to incriminate these men. Surely, a lot of people will be disappointed because Egyptians have been waiting for a long time for anyone to be held accountable in this attack, one of the worst against protesters during the uprising."
On February 1, a day before the attacks, former President Mubarak made his second speech to address the nation amid massive protests.
"The thing that pains our hearts the most is the fear that has taken over the sweeping majority of Egyptians …. the events force us to choose between chaos and stability," he said.
At least 11 people were killed in the "battle", and as many as 1,000 injured.
In July 2011, investigators found that a former speaker of Egypt's upper house of parliament was behind the attacks.
The fact-finding judicial committee ruled that Safwat al-Sharif masterminded the February 2 assault that left several protesters dead.
The investigation concluded that Sharif and other parliamentarians had hired thugs to attack crowds and that he urged them to "kill the protesters if they had to", the state-run MENA news agency reported.
The trial began in September 2011; Sharif, Fathi Sorour, former speaker of the lower house and the rest of those appearing in court denied the charges filed against them.
In October 2011, an Egyptian court acquitted the defendents because the testimony of the witnesses was weak and "driven by grudges between witnesses and the defendants due to partisan differences," according to Judge Mustafa Abdullah.
He also said some of the witnesses had criminal records, including one who had a record of perjury.
Despite the list of known victims, the judge said he trusted the testimony of a general who was a member of the council
that ruled Egypt during the transition, who said that no one was killed in the square during the battle.
