PARIS — Authorities investigating France’s deadly shooting rampage released the mother of the Islamist fanatic blamed for the killings but continue to hold his older brother and the older brother’s girlfriend, officials said Saturday.

Police are trying to determine whether 24-year-old Mohamed Merah had any help in carrying out the execution-style murders of seven people that have shocked France and refocused attention on the threat of radical Muslim terrorists.

Merah’s brother, Abdelkader, was flown to Paris for further questioning Saturday, along with his girlfriend, but a lawyer for Merah’s mother, 55-year-old Zoulika Aziri, said she had been released without charge.

Jean-Yves Gougnaud said, “She is devastated. At no time could she have imagined that her son was the one who did it.”

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