Paris police chief Didier Lallement told reporters on Friday, 4 October, that investigators had not ruled out any motive as they explore the murder of four people in a Paris police office.
Three police officers and a clerk were stabbed to death in the building on Thursday, 3 October. They have not yet been formally identified but the knifeman has been named as Mickaël Harpon.
Harpon, 45, was shot dead by a police officer after he fatally stabbed four other members of staff at an office in the Cite de France district of the French capital around 1pm on Thursday.
So what do we know about him?
Born in Martinique
Mickaël Harpon was reportedly born in Martinique, an island in the Caribbean which has been a French colony since the 17th century.
Harpon - whose surname is the French word for harpoon - was profoundly deaf but is believed to have communicated through sign language. He married in 2014 and his wife was also deaf. They had two children.
He had worked as a computer scientist at the Directorate of Intelligence of the Prefecture of Police, or DRPP, since 2003.
Some reports suggest he was frustrated professionally by his lack of career progression and had been asking for a sign language interpreter for months in a bid to express his desire for a promotion.
Conversion to Islam
The broadcaster BFMTV said he converted to Islam - the religion of his wife, Ilham - 18 months ago.
Some reports say Harpon had been “radicalised” by his wife but, although she has been questioned, there are no reports of her having been arrested.
Detectives have seized his phone and laptop, both of which they are believed to be interrogating to see if they can find proof of contact with organisations like Daesh.
The French news website Actu17 claimed Harpon had been reprimanded by his female because he had been reluctant to interact with women colleagues, possibly for religious reasons.
Christophe Crépin, spokesman for the French police union, told the Daily Telegraph: “I know this man. He worked in IT and he had long-running problems with his superior. He stabbed her first and then colleagues intervened and were stabbed as well.”
Mental Health Episode
Harpon’s wife has reportedly told police her husband woke up the night before the attack, having “heard voices” in his head.
She said he jumped out of bed at their apartment in the suburb of Gonesse and started talking incoherently.
Le Figaro reported that a neighbour said he heard Harpon shouting: "Allahu Akbar (God is Great)" around 3am.
Shot Dead in Courtyard
Harpon reportedly smuggled a ceramic knife into work, knowing it would not trigger the metal detector at the entrance, and suddenly attacked his boss and then others when they went to her assistance.
A deaf, non-native French citizen, father of 9 (sic), convert to Islam, who brought a ceramic knife to bypass metal detectors to stab his co-workers to death.— Enyon 🍃🍂🍁 (@deMontfiquet) October 4, 2019
This isn't about the murders of Michael Harpon though.
This is about the West committing suicide.#FridayMotivation pic.twitter.com/fgijyo2L8L
He reportedly ran out into a courtyard of the building where he was gunned down with a Heckler & Koch G36 rifle by a policeman who had reportedly only just joined the force a week earlier.
After the incident several of Harpon’s colleagues were reported to be in tears as paramedics treated the dying officers.
* Daesh (ISIL/ISIS/IS/Islamic State) is a terrorist organisation banned in Russia.