A deaf civilian police worker who had recently converted to Islam was shot dead in Paris today after murdering four colleagues with a ceramic knife following a 'dispute over working with female colleagues'.

Michael Harpon, 45, went on the rampage in the French capital's historic Police Prefecture, next door to Notre Dame Cathedral.

Investigators have not ruled out a possible terrorist motivation for the Thursday afternoon attack, which left a woman and three men dead.

All were repeatedly stabbed by Harpon, who had worked in the IT department at the Prefecture since 2003, in the worst loss of French police lives in a single day since World War II.

Harpon had recently been reprimanded by his female boss over his refusal to interact with women, Actu17 reported.

Within hours of the attack, anti-terrorist officers had raided Harpon's flat in an apartment block at Gonesse, a suburb some 12 miles from the scene of the attack.

His wife, Iham, was arrested, as an investigating source said that the nature of Harpon's attack corresponded with similar ones carried out by terrorists affiliated to Islamic State and Al-Qaeda.

The Paris knifeman lies dead on the ground in the courtyard of police headquarters after killing four officers in a rampage today

French police secure the area in front of the police headquarters in Paris after a knife attack which killed four including at least one policewoman on Thursday

The attack took place at the Paris police headquarters in the historic centre of the city, near the fire-ravaged Notre Dame cathedral

French police secure the area in front of the Paris police headquarters after the knife rampage today

'An investigation has been launched into a grudge the assailant may have held against his colleagues, but terrorism cannot be ruled out,' said the source.

'Many of those involved in similar attacks on the police have been Muslim converts influenced by radical terrorist groups.'

Christophe Crépin, spokesman for the union France Police Policeman in Anger, told The 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. I am told he then got hold of a firearm.'

Harpon, who was deaf since childhood, was originally from the Caribbean island of Martinique – a French overseas territory.

He had been married since 2014, and converted to his wife's religion in 2018 before they had their first child together.

An eye witness to the attack, which happened just after 1pm, said: 'I saw a man with a knife in his hand.

'He was running after a policeman. He was told to drop his knife, but he did not stop and the policeman fired.

'At first I thought it was a training exercise, but no. The policeman, who was on a break, shouted out three warnings, but the assailant would not stop. The police officer fired two shots and then the assailant fell.'

Harpon originally attacked three male officers in two offices on the first floor of the Prefecture, and then took his knife to two females – one died, and another was seriously injured.

None of Harpon's victims have been identified by name.

A ceramic knife would not have activated metal detectors, and Harpon would not have been searched.

Harpon worked directly to the Directorate of Intelligence of the Prefecture of Police, or DRPP.

An air ambulance flies over the Seine as emergency services respond to the knife rampage in Paris on Thursday

Emergency personnel stand near an air ambulance helicopter on the Pont Marie in Paris

Colleagues described Harpon as a previously trusted employee who had full security clearance and had never caused problems before.

The security crisis led to President Emmanuel Macron immediately visiting the Prefecture in person, along with his Prime Minister, Edouard Philippe, and Interior Minister Christophe Castaner.

Paris prosecutor Remy Heitz said anti-terror authorities were 'evaluating' the situation and said a murder investigation had been launched.

Prosecutor Mr Heitz told reporters at the scene that three of the dead were police officers and the fourth was an administrative assistant. A police union official had said earlier that all four were police officers.

In the aftermath of the attack today:

President Emmanuel Macron went to police headquarters to show his 'solidarity' with the force;

Witnesses described a 'panic' as gunshots rang out and weeping police officers came running out of an office;

The attacker was said to have started his rampage in an office before moving to a stairwell and then the courtyard where he was shot dead;

Police were searching the home of the suspect, who was described as a trusted employee of 20 years' experience at police headquarters;

France's interior minister said a wounded police employee was undergoing emergency surgery;

Authorities cordoned off the scene with emergency vehicles, an air ambulance and a patrol boat on the Seine.

Paris Mayor Anne Hidalgo confirmed that 'several people' were fatally wounded in the force's worst loss of life on a single day since World War II.

According to union officials, the attack began around 1pm in an office and spread out elsewhere in the large police compound near Notre Dame cathedral.

Reports said the man had attacked at least one woman in a stairwell before moving on to the courtyard where he was shot dead.

Emery Siamandi, an employee at police headquarters, said he heard gunshots and saw two weeping officers running out of a room.

A third officer, described by Mr Siamandi as the policeman who shot and killed the assailant, came out on his knees, also in tears.

'People were running everywhere, there was crying everywhere,' said Mr Siamandi, an interpreter who was in the building when the attack happened.

'I heard a shot, I gathered it was inside,' he said. 'Moments later, I saw police officers crying. They were in a panic.'

An investigating source said the attacker 'was involved in an argument with someone and then erupted in anger, targeting other police colleagues before being neutralised.'

Paramedics walk by firefighter vehicles near Paris police headquarters where the attack took place on Thursday afternoon

Paris prosecutors confirmed later in the afternoon that one woman and three men had died in the attack.

France's interior minister said a wounded police employee was undergoing emergency surgery this afternoon.

'Another colleague is in a state of shock (...) and the person behind the attack has been shot by another colleague,' said union official Yves Lefebvre.

According to BFM, authorities are now searching the 45-year-old's home while his wife has reportedly been taken into custody.

Loic Travers, another union official, said the suspected attacker was an administrative worker in the police intelligence unit.

He had been working there for 20 years and had never caused any problems before, Mr Travers said.

Interior Minister Christophe Castaner said the attacker had 'never shown any behaviour problems'.

The police were 'particularly stricken by this exceptionally grave incident', he said.

Christophe Crepin of the Police Up In Anger movement told franceinfo radio that the assailant had experienced issues with his supervisor.

'I know there were tensions between him and his direct supervisor,' he said. 'I do not think this is a terrorist act.'

The suspect was described in Le Figaro as a computer scientist born in Martinique who had a hearing impairment.

The motives of the attack are not yet known, but investigators suspect that a workplace row was behind it and one spokesman said it appeared to be an 'internal dispute'.

An official at the prosecutor's anti-terrorism office said that for now his office was not leading the investigation.

'Did he snap, or was there some other reason? It's still too early to say,' Mr Travers, who is head of the Alliance Police union for the Paris region, told BFM television.

Jean-Marc Bailleul, another police union leader, described the incident as criminal rather than an act of terror. 'It was a moment of madness,' he said.

Military forces establish a security perimeter near Paris police headquarters

Police officers patrol in a rubber boat on the Seine river after the knife rampage on Thursday

Military personnel are surrounded by emergency vehicles as they respond to the attack today

A witness to the attack told the local Parisien newspaper: 'I heard a shot, I think it was around 12.30. Around me, there were only policemen.

'They immediately unsheathed their weapons. I was very surprised to hear these shots because this is not the place where we imagine that this can happen.

'I first thought of a suicide because there are many in the police force at the moment. And then a few moments later I saw policewomen in tears.

'I thought it must be serious. The police were in panic, they were running everywhere. Many people were crying.'

The premises were cordoned off after the lunchtime attack and dozens of police and emergency vehicles converged at the scene.

An emergency message was broadcast over loudspeakers at the court of justice next door, announcing 'an attack' at the police headquarters and stating the area was 'under surveillance'.

An air ambulance also landed on a bridge across the Seine and the nearest metro station was shut for security reasons, the transport authority said.

A police spokesman said he had no comment on the incident and there has still been no official word from the force.

Interior Minister Christophe Castaner, who was due to visit Turkey later on Thursday, postponed his trip to visit the scene of the attack.

Emergency vehicles in Paris on Thursday near the police headquarters where the rampage unfolded today

The premises were cordoned off around lunchtime, and emergency services were quickly at the scene

Police vehicles are parked near the headquarters and the nearby metro station has been closed

Yesterday thousands of French police demonstrated in Paris for better working conditions, in the wake of a spate of suicides in the force, but there is no indication that today's attack was related.

Organisers estimated that 27,000 officers took part, out of 150,000 police staff nationwide.

The force has been stretched to the limit by a year of 'yellow vest' protests against Emmanuel Macron and officers have been accused of heavy-handed tactics.

France has been by a succession of attacks since 2015 including co-ordinated terror attacks and lone-wolf knife and gun attacks.

The country remains on high alert after these attacks.

In January 2015, two men armed with Kalashnikov rifles stormed the Paris offices of satirical weekly Charlie Hebdo, killing 12 people.

A policewoman was killed just outside Paris the following day, while a gunman took hostages at a Jewish supermarket, four of whom were killed.

On November 15 that year, France was hit by the worst terror attacks in its history.

Islamic State jihadists armed with assault rifles and explosives struck outside a France-Germany football match at the national stadium, Paris cafes, and the Bataclan concert hall in a coordinated assault that left 130 people dead and more than 350 wounded.

On July 14, 2016 a Tunisian ploughed a truck through a large crowd gathered for Bastille Day fireworks in the Mediterranean city of Nice. The attack killed 86 people and injured more than 400.

French police and security forces establish a security perimeter near Paris police headquarters

The premises were cordoned off around lunchtime, and emergency services were quickly at the scene