The mother of the Frenchman accused of killing seven people in a shooting rampage has been released without charge, a judicial official said Saturday.

Zoulika Aziri was freed late Friday, the official said on condition of anonymity because the information wasn’t cleared for public release.

Ms. Aziri’s son, Mohamed Merah, is blamed for a series of deadly shootings which have shocked France and upended the country’s presidential race.

Merah, who claimed allegiance to al-Qaida, died in a hail of gunfire Thursday after a dramatic 32-hour standoff with police in Toulouse.

Merah had filmed himself carrying out attacks in southern France that began March 11 and killed three Jewish schoolchildren, a rabbi and three French paratroopers with close-range shots to the head, prosecutors say. Another Jewish student and a paratrooper were wounded.

Investigators are trying to figure out whether the Frenchman of Algerian descent acted alone, and his older brother Abdelkader Merah, along with Abdelkader’s girlfriend, remain in police custody in Paris.

Key questions include how Mohamed Merah, described by French intelligence boss Ange Mancini as “a little failure from the suburbs,” was able to amass an arsenal of weapons including an Uzi sub-machinegun and rent a car, despite having no clear source of income.

Mancini told French broadcaster BFMTV that Merah told police during the siege that he bought the weapons for 20,000 euros, using money he acquired through break-ins and holdups.

Mancini said he believed that Merah was telling the truth about that, but suggested that forensic police would be examining the guns for clues as to where Merah got them.

“The weapons, too, will talk,” Mancini said.

Merah had claimed that neither his mother nor his brother knew of his plans, but police union spokesman Michel Crepin told reporters that detectives have already gathered evidence to suggest that Abdelkader may have helped his brother carry out the shootings.

Asked what police had on the brother, Mr. Crepin said there was evidence to suggest that Abdelkader Merah had “furnished means (and) worked as an accomplice.”

Mr. Crepin refused to comment further, saying it was for a judge to decide what charges, if any, to bring. Under French law if either of the two continue to be held beyond the weekend, preliminary charges will have to be filed.

Abdelkader had already come under police radar, according to officials. He was questioned several years ago about alleged links to a network sending Toulouse—area youths to Iraq, but no action was brought against him at the time.

Back in the southern French city of Toulouse, where Merah held out in an apartment building for more than a day against one of France’s most elite police units, residents were beginning to return home to inspect the damage.

Video footage shot by police of the inside of Merah’s apartment showed a shattered three-room residence strewn with debris from the fighting and gaping bullet holes in the walls.

Building resident Farida Bohama was quoted by France’s Le Figaro newspaper as saying nothing would ever be the same.

“I really want to move,” she said.

More In: International | News