PARIS — The radicalization of the French gunman who killed seven people on an eight-day shooting spree this spring began at home, his brother recounts in a new book and documentary, according to media reports.

Mohamed Merah killed three Jewish children, a rabbi and three paratroopers in and around the southern city of Toulouse in March before dying in a standoff with police. Merah claimed links to al-Qaida and said 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.