Abdelkader Merah, the older brother of infamous Toulouse "scooter killer" Mohamed Merah, was convicted of being part of a terrorist conspiracy but cleared of having a direct hand in his brother's shooting spree.
Mohamed Merah killed three soldiers in March 2012 before turning his sights on Ozar Hatorah school in Toulouse, where he gunned down a rabbi, two of the rabbi's children, aged three and five, and an eight-year-old girl.
The attack was the deadliest on Jews in France in three decades and marked the advent of a new threat from French-born radicals goaded by foreign terror groups to strike their homeland.
Merah was killed by police after a 32-hour siege at his home, three days after the school assault.
The trial of his 35-year-old brother and mentor Abdelkader was the first in connection with a string of attacks that have claimed the lives of over 240 people in France in the past five years.
Emotions ran high throughout the five-week proceedings, with the victims' families insisting that the defendant must have known of his brother's plans.
But while admitting to having been present when his brother stole the scooter he used in the attacks, Abdelkader flatly denied any knowledge of his sibling's murderous intentions.
Five judges cleared him of complicity in the attacks for lack of evidence but convicted him of a terrorist conspiracy over his support for jihad in a ruling that appeared to satisfy most of the victims' families.
"Justice has been served," Patrick Klugman, lawyer for the family of slain rabbi Jonathan Sandler said.
Olivier Morice, a lawyer for one of the murdered soldiers, also hailed the ruling.
But the mother of another of the dead servicemen, Latifa Ibn Ziaten, said his sentence did not go far enough and that her son had "died for nothing".
"We are too naive in France," she said, fighting back tears.
Merah's lawyer Eric Dupond-Moretti welcomed the court's not-guilty finding on complicity in the murders, saying it showed that "even in the worst terrorism cases, proof and the rule of law were not relegated to the role of accessories".
Struggling to be heard above the jeers from the victim's relatives Dupond-Moretti dismissed the conspiracy conviction as "a catch-up session".
A friend of the Merah brothers who supplied Mohamed with a machine gun and a bullet-proof vest was also convicted of a terrorist conspiracy.
Fettah Malki was given a 14-year sentence, which he vowed to appeal.
- From petty crime to terrorism -
The trial lifted the lid on a dysfunctional family living on the margins of society in the high-rise Toulouse suburb of Les Izards.
Three of the five Merah children, who were born to Algerian immigrant parents who divorced when they were young, came under the spell of radical Islamists.
Both Abdelkader and Mohamed spent time in prison for acts of delinquency -- an experience that radicalised the younger Merah and left him thirsting for revenge against France.
Investigators believe Abdelkader -- an ultraconservative Muslim nicknamed "Ben Ben" by neighbours over his admiration for Al-Qaeda leader Osama bin Laden -- had considerable influence over his brother.
Defending his sibling's killings directly after the attacks in 2012, he declared: "Every Muslim would like to give his life to kill his enemy."
In 2011, Mohamed travelled to the lawless tribal regions of Pakistan near the border with Afghanistan to join the Qaeda-affiliated Jund al-Khalifa.
Returning to France, he was questioned by intelligence services but insisted his trip had been solely for tourism.
Prosecutors had presented Abdelkader as the real brains behind the attacks and called for him to be given life in prison, without possibility of parole for 22 years.
But Merah's lawyers said the court should to make him a scapegoat for his brother's crimes to satisfy the public's desire for a conviction.