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French police and security forces establish a security perimeter near Paris police headquarters after a disgruntled employee fatally stabbed four people.

French prosecutors are now probing the fatal knife attack that killed three officers and an administrator outside Paris police headquarters this week as a potential act of terrorism.

Disgruntled administrative employee Mickaël Harpon, 45, who was deaf, attacked three members of the police force’s intelligence division Thursday inside two ground floor offices, and then went into a stairwell where he assaulted two women, according to reports.

Investigators researching the civilian employee found elements that led them to probe the case “in relation with a terrorist enterprise,” the Paris prosecutors’ office said Friday.

The office did not provide any additional details.

The terrorism investigation marked a reversal from earlier in the day, when government spokeswoman Sibeth Ndiaye told FranceInfo that prosecutors opened a murder investigation on facts “which are not falling under terrorism at this stage of the investigation.”

Authorities dug into Harpon’s computer and cell phone — and spoke with his wife and witnesses — for any clues as to his motive.

Harpon’s wife told French media that her husband suffered a psychotic episode, was incoherent and heard voices the night before, the BBC reported.

Police union official Christophe Crépin told FranceInfo that there had been tensions between Harpon and his supervisor.

“I do not think this is a terrorist act,” said Crépin, who knew Harpon.

And police union leader Jean-Marc Bailleul told French-language station BFMTV that the stabbing spree was “a moment of madness.”

The attacker was gunned down in a courtyard at the police facility by an officer described as a young “police trainee.”

One of the women he allegedly stabbed survived and underwent emergency surgery after the attacks. She was listed in critical condition.

With Post wires