Knife-wielding IT worker kills four at Paris police HQ

A knife-wielding man who worked at police headquarters in central Paris went on a rampage Thursday, stabbing to death four employees before himself being shot dead, officials said.

A fifth person was critically injured and was being treated in hospital after the deadliest attack on police in France in years, the motive of which was still unclear.

Sources close to the investigation said the attacker, a 45-year-old IT worker in the police intelligence department, had converted to Islam 18 months ago.

He killed three male officers and a female assistant before being shot in the courtyard of the square stone building next to Notre-Dame cathedral in the historic heart of Paris.

The man, who was born in the French Caribbean territory of Martinique and had worked for the police since 2003, had a hearing disability.

Police searched his home in a quiet residence in Gonesse, a low-income suburb north of Paris, and took his wife into custody, Heitz told reporters.

Interior Minister Christophe Castaner said the assailant had "never shown any behavioural problems".

The police were "particularly stricken by this exceptionally grave incident", said Castaner, who postponed a planned trip to Greece and Turkey to visit the scene with President Emmanuel Macron.

The assailant used a kitchen knife to stab the three policemen in their offices before going on to attack the female employee on the staircase.

In the courtyard, he was confronted by an officer who ordered him to drop the knife. When he refused, the officer shot him in the head, police sources said.

Heitz said he was "in constant contact" with anti-terrorism investigators about the case but that for the moment it was being handled by his office.

The police building was cordoned off after the lunchtime attack in the historic centre of Paris, near Notre-Dame cathedral, and dozens of police and emergency vehicles converged at the scene.

"People were running everywhere, there was crying everywhere," said Emery Siamandi, an interpreter who was in the building when the attack happened.

"I heard a shot, I gathered it was inside," he told AFP. "Moments later, I saw police officers crying. They were in a panic."