A French judge filed preliminary murder and terrorism charges against Abdelkader Merah, whose younger brother Mohamed Merah claimed responsibility for the attacks.
Abdelkader Merah remains in custody and has not spoken publicly. His lawyer Anne-Sophie Laguens said that "no one was aware of anything."
Investigators say Abdelkader Merah celebrated what he considered the martyr-like death of his brother on Thursday. Mohamed Merah was killed in gunfire with police.
Authorities say Mohamed Merah taped himself killing seven people over several days, including three Jewish schoolchildren.
Investigators believe Abdelkader Merah helped prepare the killings and are investigating whether the two were linked to an international network or worked on their own.
Laguens denied reports that Abdelkader Merah was proud of his brother's actions.
The Associated Press contributed to this report.