The investigation into the murder in France of a teacher for showing cartoons of the Prophet Mohammed in class turned to Syria on Thursday (October 22nd), where the killer had an extremist contact, a source close to the case said.

Seven people have been charged with being complicit in a "terrorist murder" after 18-year-old Chechen Abdullakh Anzorov killed Samuel Paty on Friday, including two teenagers who helped him identify the teacher.

France paid homage to Paty on Wednesday, with President Emmanuel Macron saying that the history and geography teacher had been slain by "cowards" for representing the secular, democratic values of the French Republic.

In their search for accomplices, anti-terror investigators have now established that Anzorov had contact with a Russian-speaking extremist in Syria whose identity is not yet known, the source told AFP.

Le Parisien newspaper reported on Thursday that Anzorov's suspected contact had been located through an IP address traced back to Idlib, an extremist holdout in north-western Syria.

In an audio message in Russian immediately after the killing, translated by AFP, Anzorov referenced the Qur'an and the "Islamic State of Iraq and Syria" several times.

The message was published on social media in a video, accompanied by two tweets, one showing the victim's severed head and another in which Anzorov confessed to the murder.

Moments later he was shot dead by police.

Anzorov decapitated Paty with a long knife. Many of Paty's students saw the images online before they could be taken down.

The teenagers who pointed out Paty to his killer in return for money were late Wednesday charged over the killing.

The parent of one of Paty's pupils, who started the social media campaign against the teacher even though his daughter was not in class when the cartoons were shown, was also charged.

More than 50 organisations to be dissolved

Also charged was a known Islamist radical who helped the father stir up outrage against Paty.

The other three facing prosecution are friends of Anzorov, one of whom allegedly drove him to the scene of the crime while another accompanied him to purchase a weapon.

Two of them also face charges of being complicit in terrorist murder while the third was charged with a lesser offense, the anti-terrorist prosecutor's office said.

Paty, 47, became the target of an online hate campaign over his choice of lesson material -- the same images which unleashed a bloody assault by Islamist gunmen on the offices of satirical magazine Charlie Hebdo in January 2015.

Police have carried out dozens of raids since the crime, while the government has ordered the six-month closure of a mosque outside Paris and dissolved the Sheikh Yassin Collective, a group they said supported Hamas.

The French government has earmarked for dissolution more than 50 other organisations it accuses of having links to radical Islam.

Paty's beheading was the second knife attack in the name of avenging the Prophet Mohammed since a trial of alleged accomplices in the Charlie Hebdo attack started last month.