PARIS (AP) — A memorial march will be held Tuesday evening near Paris in homage to the history teacher who was beheaded last week, while French police said 16 people remain in custody as part of the investigation into the attack.

Local elected officials, teachers and parent’s associations called on people to dress in white for the march at 6:30 p.m. (1630 GMT; 12:30 p.m. EDT) in Conflans-Sainte-Honorine, northwest of Paris, which will take place near the high school where Samuel Paty was teaching.

Paty was beheaded on Friday by an 18-year-old Moscow-born Chechen refugee, who was later shot dead by police. Police officials said Paty had discussed caricatures of Islam’s Prophet Muhammad with his class, leading to threats.

France’s lawmakers will also gather for a ceremony and a minute of silence on Tuesday at the National Assembly.

A French judicial official said on condition of anonymity because he wasn't authorized to disclose information on an ongoing investigation that 16 people, including family members of the attacker, were in police custody Tuesday. Judicial authorities have already opened an investigation for murder with a suspected terrorist motive.

Meanwhile, Interior Minister Gerald Darmanin announced the closure of a mosque which had posted a message on social media denouncing the teacher’s course about the caricatures.

Darmanin said on Monday evening that he had ordered the closure of the mosque in Pantin, a suburb northeast of Paris, for six months. Speaking on French television TF1, Darmanin said that the mosque's leader "relayed the message which consisted in saying that this teacher should be intimidated” and mentioned the address of the school.

Darmanin had previously said authorities were also looking into about 50 associations suspected of encouraging hate speech and the issue will be discussed at a Cabinet meeting Wednesday.

A national memorial event will be held Wednesday evening to pay tribute to Paty in the courtyard of La Sorbonne university in Paris. The centuries-old site is a symbol of knowledge and education and of the “spirit of Enlightenment” since it has always been “a forum to express ideas and freedoms,” the French presidency said.