The radicalisation of the French gunman who killed seven people in March began at home, his brother has said in a new book and documentary.

Mohamed Merah killed three Jewish children, a rabbi and three paratroopers in and around Toulouse over eight days in March before dying in a standoff with police. Merah said he had links to al-Qaida and that he had received training at an Islamist paramilitary camp in Pakistan.

One of his brothers, Abdelkader, also faces preliminary charges in the case and is in police custody.

The attacks raised painful questions about whether France was failing to integrate the children of Muslim immigrants, like the Merahs, who are of Algerian origin. Many blamed the poverty of the neighbourhoods that many immigrants and their children live in for driving them to radical Islam.

But in the book, another of the Merah brothers, Abdelghani, says his parents, particularly his mother, were responsible for Merah's radicalisation. According to excerpts published in Le Figaro and other newspapers, Abdelghani made a silent vow on the day of his brother's funeral to tell the world how they were brought up on anti-Semitism.

"I will explain how my parents raised you in an atmosphere of racism and hate before the Salafis [ultra-conservative Muslims] could douse you in religious extremism," he writes in My Brother, That Terrorist, due out on Wednesday. The Merahs's mother was at one point held for questioning but has since been released. Their father left the family for Algeria when the children were young but has since sued the French state for Mohamed's death.

A documentary featuring interviews with Abdelghani and his sister, Souad, treads similar ground and airs later on Sunday on French television.

In an excerpt published in the Belgian media, Abdelghani remembers how his mother drove home a message of anti-Semitism.

"My mother always said: 'We, the Arabs, we were born to hate Jews.' This speech, I heard it all throughout my childhood," Abdelghani says in the documentary, according to the RTL.be website.

Souad, on the other hand, declares how proud she is of her dead brother.