Netanyahu at Toulouse
Netanyahu at Toulouse Avi Ohayon, GPO

The sister of Mohamed Merah, who shot seven people dead, including four at a Jewish school, in Toulouse in March, is the subject of a criminal investigation after declaring herself proud of her brother in a television documentary, judicial sources said Monday.

AFP reported that the probe will establish whether Souad Merah breached French legislation that prevents individuals from publicly defending terrorist acts.

A program broadcast by the M6 channel on Sunday included secretly-filmed footage of the sister saying she was "proud" of her brother for "fighting to the end."

France’s Interior Minister Manuel Valls described her statements as "an apology for terrorism and anti-Semitism and a provocation to religious and racial hatred."

Mohamed Merah, a self-described Al-Qaeda sympathizer, shot a rabbi, three Jewish schoolchildren and three French paratroopers in attacks in and around the southern city of Toulouse in March before being shot dead in a police siege.

It has since emerged that he could have been, and probably should have been, stopped by the authorities, who had been monitoring him and his links to radical Islamist groups since 2006.

The 23-year-old terrorist had shot footage of himself carrying out the seven murders in Toulouse. He confessed to murdering the soldiers, the rabbi and the Jewish children while hiding in his apartment during the siege by SWAT police officers prior to his death.

Merah’s father has filed suit against police who killed him, accusing police of murdering his son.

Merah's brother, Abdelghani Merah, has said his brother was “brainwashed” to hate Jews by his family, says.

His parents, and especially his mother, were essentially responsible for Mohammed's actions, said the brother. He is writing a book on the matter, called “My Brother, That Terrorist.”