The 18-year-old Chechen refugee who decapitated a schoolteacher near Paris had ISIS links, French authorities said. Video and images of the gruesome killing carried out by Abdoulakh Anzorov were sent to fellow Russian-speaking ISIS supporters and have been shared by Chechen pro-ISIS accounts on the Telegram messaging service. Jean-Francois Ricard, the prosecutor leading the investigation, also said that Anzorov’s half-sister had travelled to Syria in 2014 to join ISIS, deepening suspicions of his ties to the terror group. The woman has been investigated by anti-terrorist police. In an attack that has shocked France, Anzorov decapitated Samuel Paty after the teacher gave a lesson two weeks ago in which he showed pupils cartoons of the Prophet Mohammed to illustrate the idea of free speech. A parent of a Muslim girl who attended the class then waged a social media campaign against the 47-year-old history teacher, accusing him of Islamophobia. Anzorov arrived at the middle school in the quiet town of Conflans-Ste-Honorine, just north of Paris, on Friday afternoon and asked pupils to point out Paty. He confronted Paty then shouted “Allahu akbar” as he hacked at him with a long knife. Afterwards he posted a video online showing the man’s severed head and denouncing President Emmanuel Macron as the “leader of the infidels”. He added: “I have executed one of your hell-hounds who dared to belittle Mohammed.” The images are said to show the victim’s head lying on the road and a message from Anzorov confessing to the killing. Anzorov was still wielding a knife and an Airsoft pellet-firing gun when he ran towards police trying to stab them. Ignoring commands to surrender he was fatally shot. Another 35-centimetre blood-covered knife was found nearby. Flowers have been laid at the school gates and one parent wrote on Twitter: “[My daughter] is in pieces, terrorised by the violence of such an act.” Anzorov’s uncle told French television that he suspected his nephew had been radicalised by online ISIS propaganda that drove him to the killing. “He was a child. He was only 18,” said the unnamed man. “If he were still alive, I would have asked him: ‘Why did you do that? What was going on your head?' He must have been influenced by someone.” He offered his condolences to Paty’s family, adding: “The Chechen community is not like that.” Anzorov’s parents, grandfather and teenage brother were taken in for questioning after the attack. Jean Castex, the prime minister, described the murder as a “vile attack on secularism, the backbone of the French Republic”. The killing is the second extremist-linked attack in France since the trial began last month of 14 alleged accomplices of terrorists who five years ago killed 12 people working for <em>Charlie Hebdo</em> magazine in response to its publication of cartoons of the Prophet Mohammed.