Paris stabbing: Police hunt for motive in deadly attack as government says no suggestion of terrorism

Investigators search attacker's computer and mobile phone for indications of motive

Interior minister Christophe Castaner said on Thursday that the attacker had never shown any behavioural problems (EPA)

There is nothing to suggest that the employee who stabbed four colleagues to death at Paris’ police headquarters was radicalised, the French government has said.

Investigators are searching for possible motives for the knife attack on Thursday.

The assailant, a 45-year-old technology administrator in the intelligence unit of the Paris police, was shot dead after the attack.

Sibeth Ndiaye, a government spokesperson, said prosecutors have decided to open a murder investigation on facts "which are not falling under terrorism at this stage of the investigation".

Investigators have been scouring the attacker's computer and mobile phone for any indications of a motive and have interviewed his wife and witnesses, a police official said.

The man, who converted to Islam 18 months ago, was not believed to have been radicalised and had no history of psychiatric problems, according to the official.

Christophe Castaner, the interior minister, said on Thursday that the man had never shown any behavioural problems.

News broadcasters France Info and BFM TV said the attacker's wife told police that her husband, who was deaf, had visions and made incoherent statements on the night before the attack.

Noam Anouar, from the Vigi police union, said the assailant had security clearance to work in the police intelligence unit.

When asked about the ceramic knife the assailant took into the building, Laetitia Vallar, a spokesperson at the Paris police, said on BFM TV that officers and administrators could enter the building with their badges under an officer's supervision.

They were not submitted to bag searches and security screening like the public.

She added that psychological assistance was being offered to officers and employees.

The knife attack left three officers and an administrator dead. Another person was seriously injured.

Police held a minute of silence in the headquarters' main courtyard on Friday morning.

Associated Press