Police targeted the homes of around 80 individuals that posted messages in support of the attacker, who reportedly killed teacher Samuel Paty after he had shown caricatures of Islam's founder, Mohammed, in a class on the freedom of expression to his 13-year-old students.
The reported killer – who was shot by police after the murder – was 18-year-old Abdoulakh Anzorov, a Chechen refugee from Russia who was granted residency in France this year.
Police are also conducting raids on 51 Islamic associations in the area. Ten individuals have been detained thus far, including the father of one of the students in Paty's class, who reportedly had been campaigning against the teacher with others online.
"They apparently launched a ‘fatwa' against the teacher," said Gerald Darmanin, the French Minister of the Interior, referring to the Islamic practice of calling for someone's death due to apostasy.
Four children are also being held by police, who believe they helped Anzorov to identify Paty in exchange for money.
Thousands marched in demonstrations across France on Sunday in solidarity with Paty.
🔦 The caricatures of Mohammed that Paty showed in class were reportedly from the French publication Charlie Hebdo, which was attacked by Islamic terrorists in 2015, leaving 12 dead.