Five people associated with the man who carried out a deadly knife attack at the headquarters of the Paris police this month have been arrested, a source close to the investigation told Reuters on Monday, confirming earlier media reports.

The arrests took place early on Monday morning in the Val d'Oise region in the Paris suburbs area.

On Oct. 3, Mickael Harpon, a 45-year-old IT specialist with a security clearance, killed three officers and one civilian employee before he was shot dead by another police officer.

Harpon was born on the French island of Martinique and had worked at the police headquarters for several years. He converted to Islam about 10 years ago.

Last week, three sources close to the police said the French police had re-opened an internal investigation into the suspected Islamist sympathies of a senior police officer as part of a security review after the rampage.

- Reuters