Police descended on the homes of dozens of suspected Islamist militants across France on Monday in connection with the “fatwa” decapitation killing of a teacher by a Chechen Muslim teen. Interior Minister Gerald Darmanin said about 80 investigations were under way into online hate speech in France and that more would take place. A police source told Reuters late Sunday that France was preparing to expel 231 foreigners on a government watch list for suspected extremist religious beliefs. Eleven people were in custody, including a school parent who Darmanin said is suspected of calling on social media for Friday’s killing of the educator.

More than a million people demonstrated in cities across France on Sunday to show their support for freedom of expression for Samuel Paty, the teacher who was attacked after he is said to have shown cartoons of the Prophet Muhammad to pupils as part of a classroom discussion. Police say Paty, 47, a history and geography instructor, was hacked to death by a teenage Islamist after Muslim parents ran a social-media campaign against him for showing the images. Paty, the father of a 5-year-old boy, taught in a secondary school in Conflans-Sainte-Honorine on the outskirts of Paris. He was targeted by Abdullah Anzorov, an 18-year-old refugee, as he left the school on Friday. Anzorov, who was shot dead by police after the murder, was born in Moscow to a family from Chechnya, the Muslim Russian republic. His family moved to France when he was 6. He lived in Evreux in Normandy and had no apparent connection with Paty. Jean-Michel Blanquer, the education minister, who was among several cabinet members present at the demonstrations, said, “A teacher is perfectly entitled to show the cartoons.”