French President Emmanuel Macron vowed an "unrelenting fight" against Islamist extremists on Tuesday as he paid tribute to the four Paris police staff stabbed to death last week by a radicalized colleague.
Mickael Harpon, a 45-year-old computer expert in the police intelligence-gathering department, used a kitchen knife and an oyster shucker to kill three male and one female colleague in a 30-minute rampage that ended when an officer shot him in the head.
The attack in the police's inner sanctum caused shock in France, where the government is being pressed to answer how Harpon's radicalisation went unnoticed, despite him having high-level security clearance.
"We will wage an unrelenting fight in the face of Islamist terrorism," Macron vowed at a ceremony at the police headquarters near Notre-Dame cathedral where the attack took place.
Macron said it was "inconceivable and unacceptable" that Harpon, who had worked for the police since 2003, had managed to carry out an attack "in the very place where we pursue terrorists and criminals".
He blamed the attack on "a distorted, deadly Islam" which he vowed to eradicate and vowed to build in France a "society in a state of vigilance".
At the same time, he warned against lapsing into a climate of permanent suspicion, assuring: "This is not a fight against a religion but against the distortion of it which leads to terrorism."
Thursday's attack brought to 255 the number of people killed in attacks blamed on, or claimed by Islamist radicals since 2015.
Harpon, a father of two, had converted to Islam about 10 years ago and adopted increasingly radical beliefs.
He had been in close contact with a hardline Salafist imam in the months before his rampage last week, according to investigators.
French President Emmanuel Macron vowed an "unrelenting fight" against Islamist extremists.