Four school students are among 15 people who have been taken into custody in France following the beheading of teacher Samuel Paty, who showed controversial cartoons of the Prophet Muhammad to his pupils.
BBC News reports the other detainees include four family members of the killer, a father at the school and a known Islamist radical.
Police in France carried out some 40 raids on the homes of suspected radicals and more raids are expected.
The brutal killing has shocked France.
Tens of thousands of people took part in rallies across France to honour Paty and defend freedom of speech.
A ceremony paying tribute to Paty, who was 47, will be held at the Sorbonne University in Paris tomorrow.
[Source: BBC News]