Anti-terror probe opened into Paris police knife murders
France has opened an anti-terror investigation into Thursday's knife attack in Paris police headquarters in which four people were killed.
Initially treated as a criminal case, the decision to hand the investigation over to anti-terror prosecutors was prompted by analysis of the dead man's mobile phone, according to French reports.
It is understood that the killer had bought a 33cm ceramic knife in the morning before his killing spree.
According to Le Parisien, at least one of the victims had their throat slit. The killer had been reported to police for unknown reasons after the terror attack against satirical magazine Charlie Hebdo in January 2015.
The development came amid confusion over the killer's motives.
Mickael Harpon 45, had worked in the IT department of the closely-guarded police intelligence unit for 20 years.
His wife had initially told investigators her husband, who had a severe hearing disability, had displayed "unusual and agitated behaviour" the night before his crime and suffered a "fit of dementia".
He had brutally woken her up, saying he had heard voices, before going to work, she reportedly told police.
Harcourt had converted to Islam about 18 months ago but police cited no evidence that his crime was driven by radical religious ideology.
Police sources said that he had a very "shy and fragile" personality.
On Friday morning, Paris' police chief, Didier Lallemand, said that all lines of inquiry remained open.
"But it is important to emphasise - you are not a terrorist because you are Muslim and converting to Islam is not an automatic sign of radicalisation. The facts need to be looked at carefully" government spokeswoman Sibeth Ndiaye told France Info.
Harpon went on the rampage at Thursday lunchtime, killing his boss, two other officers and an administrative worker with a ceramic kitchen knife before being shot dead by a policeman in the courtyard of the building - a stone's throw from Notre-Dame cathedral.
Two others were injured in the frenzied attack but their lives are no longer in danger.
Police said Harcourt had been working in IT at the police intelligence unit since 2003 and was a well-respected if taciturn member of staff.
He and his wife, who also has a serious hearing impairment, communicated via sign language. According to BFMTV, Harcourt had been frustrated at work at not being promoted and had for several months requested a sign language interpreter in the hope of moving to a network design post - to no avail.
Thursday's killings came a day after thousands of police officers staged a "march of anger" in Paris over working conditions, low morale and suicides.
They say they have been stretched to the limit after months of containing weekly "yellow vest" anti-government demonstrations, and years of high alert following a string of terror attacks in France.
