Merah's mother, Zoulaikah Aziri, who was questioned by police Friday, expressed feelings of guilt and remorse, Radio France Internationale reported.
Merah, who claimed to be an al-Qaida member, shot and killed seven people -- three soldiers, three Jewish children and a trainee rabbi -- in and around Toulouse between March 11 and 19 during three separate incidents.
He was shot and killed by France's elite RAID police squad after a 32-hour standoff in his apartment Thursday.
Aziri's attorney, Jean-Yves Gougnaud, said the mother was wracked with guilt and remorse.
"She's angry," Gougnaud said. "She is wondering why her son did this and blames herself somewhat."
Merah's bother, Abdelkader, on the other hand, said he was "proud" of his brother.
Abdelkader and his girlfriend were transferred from Toulouse to Paris Saturday for questioning by anti-terrorist police, RFI reported.
Abdelkader, a known jihadist supporter, allegedly told police he was present when the scooter used to get to and away from the shootings was stolen.
Meanwhile, police said Saturday they found the gun used in the three shootings, The Daily Telegraph reported.
The gun was found in Merah's apartment, police said.