A friend of the Paris knife attacker was arrested in Strasbourg on Sunday. The police left the building in Strasbourg's L'Esplanade neighbourhood with a handcuffed man, who was wearing a black T-shirt reading 'Grozny', the capital of Chechnya, and depicting a drawing of a Kalashnikov. A second man was also reportedly taken away by the police, but not handcuffed. According to sources, the... Еще arrested man was «the closest individual» to the assailant, who lived in Strasbourg for several years. The man is being held is being held for questioning by investigators from the General Directorate of Internal Security (DGSI). French authorities have opened a terrorism investigation into the stabbing attack, which was claimed by the self-proclaimed Islamic State (IS; formerly ISIL/ISIS). On Saturday evening, the knife-wielding attacker, identified as 21-year-old French national Khamzat Azimov, born in Chechnya in 1997, killed one person and injured four more. The assailant was killed after being shot by police. Parents of the attacker have been taken in for questioning. Footage released by Dernieres Nouvelles d'Alsace (DNA).