PARIS — Six teenagers are on trial Monday in Paris for their alleged roles in the beheading of a teacher who showed caricatures of the prophet of Islam to his class, a killing that led authorities to reaffirm France’s cherished rights of expression and secularism.

Samuel Paty, a history and geography teacher, was killed on Oct. 16, 2020, near his school in a northwest Paris suburb by an 18-year-old of Chechen origin who had become radicalized. The attacker was in turn shot dead by police.

Paty’s name was disclosed on social media after a class debate on free expression during which he showed caricatures published by the satirical newspaper Charlie Hebdo, which triggered a newsroom massacre by extremists in January 2015.

All hearings at a Paris juvenile court are to be held behind closed doors in accordance with French law regarding minors.

The defendants arrived Monday morning at the Paris court, their faces hidden behind masks and hoods, accompanied by their families. The media are not allowed to disclose their identity.

Among those going on trial, a teenage girl, who was 13 at the time, is accused of making false allegations for wrongly saying that Paty had asked Muslim students to raise their hands and leave the classroom before he showed the cartoons. She later told investigators she had lied. She was not in the classroom that day and Paty did not make such a request, the investigation has shown.

Five other students of Paty’s school, then 14 and 15, are facing charges of criminal conspiracy with the aim of preparing aggravated violence to be committed.

Read Related Also: Suspect arrested in possible hate crime shooting of 3 Palestinian college students in Vermont

They are accused of having waited for Paty for several hours until he left the school and of having identified him to the killer in exchange for promises of payments of 300-350 euros ($348-$406).

The investigation established that the attacker knew the name of the teacher and the address of his school, but he did not have the means to identify him.

The lawyer for one of the defendants, Antoine Ory, said his client is “tormented by remorse and very much afraid of the confrontation with Mr. Paty’s family.” He said the teenager “obviously didn’t know about the criminal plan” of the killer, Abdoullakh Anzorov, a Moscow-born Chechen refugee.

Ory said his client since then had “difficult” times, changed schools and friends and now sees the trial as an opportunity to turn the page.

All six teenagers are facing 2 1/2 years in prison. The trial is scheduled to end on Dec. 8.

Louis Cailliez, the lawyer for Paty’s sister, Mickaëlle, said she wants “to understand the real causes” that led the students to commit something irreparable. He pointed to the “fatal combination of little acts of cowardice, big lies, calumnies, arrangements, complicity and help without which Samuel Paty would still be alive.”