PARIS – Nine people have been arrested in connection with the beheading of a French school teacher who had shown cartoons of the Prophet Muhammad to his pupils, police said on Saturday.

Samuel Paty, a 47-year-old secondary school history and geography teacher, was killed by a knifeman in the street on Friday afternoon.

French prosecutor Jean-François Ricard said the suspected attacker was an 18-year-old born in Moscow of Chechen origin who was not known to the country’s intelligence services.

He lived with his family in Evreux, Normandy, about 100 kilometers northwest of Paris.

Nine people, including the suspect’s friends, parents, grandfather and younger brother, have been arrested in connection with the attack.

The father of one of the victim’s students and another man have also been detained on suspicion of launching a campaign against the teacher after he showed the satirical cartoons to his students.

Ricard explained that Paty had shown the drawings to his class during a lesson on freedom of expression and civil education.

The father of a Muslim student complained on social media, posting several videos in the following days in which he identified the teacher, gave his telephone number and the address of the school where he worked.

He and the other man, who was being monitored by anti-terrorist police, also complained to the school demanding Paty be fired.

Paty was murdered near the College du Bois d’Aulne where he taught in Conflans-Sainte-Honorine, about 30 kilometers from Paris, shortly before 5:00 pm Friday.

A photograph of the beheaded teacher was posted on Twitter moments later.

Police apprehended his suspected killer in the neighboring town of Eragny and he was shot dead after allegedly refusing to comply with instructions and behaving in a threatening manner.

Witnesses reportedly heard the attacker shout “Allahu Akbar” (“God is great” in Arabic) during the incident.

European Commission President Ursula von der Leyen condemned the attack on Saturday, expressing her condolences to those affected and saying her thoughts were with teachers in France and Europe.

“Without them, there are no citizens. Without them, there is no democracy,” she said in a statement.

French President Emmanuel Macron has described the killing as an “Islamist terrorist attack” and said the killer “wanted to strike down the republic and its values.”

French authorities have been on alert since last month’s start of the trial of 14 people accused of involvement in the January 2015 attacks on the offices of satirical weekly Charlie Hebdo and a kosher supermarket, which left 17 dead.

Charlie Hebdo marked the trial by republishing the Prophet Muhammad caricatures that sparked the 2015 bloodbath and al-Qaeda responded with death threats against the newspaper’s staff.