The political pressure on the government meanwhile did not let up, with two senior politicians questioning the handling of the crisis.
Abdelkader Merah denied any involvement in the shootings of three French soldiers, three Jewish schoolchildren and a trainee rabbi in three attacks claimed by his younger brother Mohammed Merah, 23.
Mohammed Merah, who said he had links to Al-Qaeda, was killed Thursday in an exchange of gunfire after a prolonged stand-off with police at his apartment in Toulouse, southwest France.
Abdelkader Merah's lawyer Anne Sophie Laguens on Sunday denied earlier reports that he had said he was proud of his brother's actions.
"He is not at all proud of the acts of his brother, as was said in the press," she told reporters in Paris. "He strongly condemns them.
"He hopes he doesn't become a scapegoat," she added.
Her client denied all the charges against him, she said.
Abdelkader Merah, 29, now stands at the centre of the investigation into his brother's lethal rampage.
Police and prosecutors have described Abdelkader Merah as a more radical Islamist than his brother who had long been known to police for what they called his "fundamentalist religious convictions".
They considered him a hardline Islamist who had played a part in radicalising his younger brother, a police source said.
During the siege however, Mohammed Merah had told police he had taught himself from the Koran while in prison, dismissing the idea that his brother had influenced him.
The elder Merah and his girlfriend, Yamina Mesbah, were taken in for questioning on Wednesday.
While Mesbah was released without charge on Sunday, Abdelkader Merah was taken from the French police's anti-terrorist headquarters in a Paris suburb to face an investigating judge in the city's central courts.
There, he was indicted for complicity in the murders and conspiracy to prepare acts of terrorism.
As police surrounded Mohamed Merah's Toulouse apartment last week, the gunman claimed responsibility for all three attacks.
In the first two incidents he shot dead three soldiers in attacks in Toulouse and nearby Montauban.
Then last week he opened fire at a Jewish school in Toulouse, killing a 30-year-old teacher, his sons aged five and four, and a seven-year-old girl.
Police have said he filmed his attacks with a camera strapped to his body and had planned to post the footage online.
Thousands of people across France paid homage to the victims Sunday.
Local politicians and religious leaders joined a silent procession in the district of Toulouse where the attack on the Jewish school took place, many people clutching roses or small French flags.
Police estimated some 6,000 took part.
"We're marching this afternoon to defend the values of France we love: Solidarity, respect for others, justice," France's chief rabbi Pierre Cohen said.
When the march arrived at the site of the attack on the school, mourners laid wreaths of flowers under a banner featuring portraits of those who died there.
Hassen Chalghoumi, the imam of Drancy, just north of Paris, paid a tearful tribute to the victims.
He had come to the march to denounce the violence "and to say that Islam, it isn't that," he told reporters later.
In Paris, thousands more attended another silent march in tribute to those killed, many carrying the French tricolour: 20,000 according to the anti-racism groups who organised the event; 2,800 according to police.
Smaller marches took place in other parts of the country.
Two senior politicians spoke out on Sunday, questioning the government's robust defence of how the crisis had been handled.
"The Republic has some questions to answer," Francois Bayrou, leader of the centrist MoDem party and a candidate for the presidency, told an election rally in Paris.
How did an unbalanced killer known to the authorities -- and already on a US flight-ban list -- manage to train himself, acquire weapons and carry out these killings without any alert being sounded, he asked.
Eva Joly, presidential candidate for the Europe Ecology-Green Party, called for Bernard Squarcini, head of the DST domestic intelligence agency, and national police chief Frederic Pechenard to quit over the affair.