Mohamed Mogouchkov, 20, was caught on video carrying out a knife attack at Gambetta high school in Arras, France.
Dominique Bernard, 40, was killed. Two other adult victims were seriously injured.
Mogouchkov is a “refugee” of Chechen origin. He was previously sentenced to 18 months in prison for distribution of ISIS literature. He was then added to a national security watchlist instead of being deported.
Mogouchkov is said to be a former student at the High School.