A suspect shot dead by police after the beheading of a history teacher near Paris was an 18-year-old Chechen refugee unknown to intelligence services who posted a grisly claim of responsibility on social media minutes after the attack, officials said Saturday. France’s anti-terrorism prosecutor’s office said authorities investigating the killing of Samuel Paty in Conflans-Sainte-Honorine on Friday arrested nine suspects, including the teen’s grandfather, parents and 17-year-old brother. Paty, who was 47, had discussed caricatures of Prophet Muhammad with his class, leading to threats, police officials said. Islam prohibits images of the Prophet, asserting that they lead to idolatry. The officials could not be named because they were not authorized to discuss ongoing investigations.