PARIS -- France’s anti-terror prosecutor said Tuesday that a suspected Islamic extremist declared allegiance to the Islamic State group before fatally stabbing a teacher in a school attack last week.

The prosecutor, Jean-François Ricard, said an audio recording in the suspect’s phone. In it, the alleged attacker declared allegiance to the Islamic State and expressed “his hatred for France, for the French, for democracy and the education he benefitted from in our country.”

The alleged attacker was a former pupil of the school in the northern town of Arras. A teacher was fatally stabbed in the neck and three other people injured in the assault that prompted France to raise its terror alert level and deploy extra security.

The prosecutor spoke at a press conference and took no questions.

Ricard said that shortly before the stabbing, the alleged attacker also recorded a 30-second video of himself in front of a war memorial.

In that video, the attacker “repeatedly attacked, in his own words, the values of the French. He expressed some particularly threatening views,” the prosecutor said.