The deranged employee who stabbed four people to death — including three cops — inside a Paris police headquarters had converted to Islam 18 months ago, according to a report.

The 45-year-old deaf IT worker — identified in media reports as Michael Harpon attacked three members of the police force’s intelligence division Thursday inside two ground floor offices, then went into a stairwell and assaulted two women, French newspaper Le Parisien reported.

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

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

Harpon, a native of the island of Martinique, married in 2014, and he and his wife lived in a quite suburb north of Paris, according to Le Parisien.

He converted to Islam 18 months ago but neighbors told local reporters that there were no signs he was radicalized — nor are police in Paris treating the incident as a terrorist attack.

French authorities took the man’s wife into custody in the aftermath of the grisly attack, according to CNN.

The fifth victim in the stabbing was in serious condition and underwent surgery Thursday.

With Post wires