An ISIS fanatic who stormed the house of a French police chief and murdered him and his wife may have already known him and carried out the killings in revenge for an earlier run-in, it has been claimed.

Larossi Abballa, 25, stabbed Jean-Baptiste Salvaing to death outside his home in Magnanville near the French capital on Monday.

Afterwards he took the police officer's wife Jessica Schneider, 36, hostage before killing her but spared their three-year-old son.

ISIS fanatic Larossi Abballa, who stabbed Jean-Baptiste Salvaing and his wife Jessica Schneider to death at their home near Paris. It has now emerged he may have had an earlier run in with Mr Salvaing, a police commander

Mr Salvaing with his wife Ms Schneider, both of them were killed by the ISIS fanatic in front of their three-year-old son

After killing the couple, Abballa posted a 12 minute monologue on Facebook Live, showing the crime scene before he was killed when police stormed the house.

Now as police probe why Mr Salavaing, 42, was targeted by Abballa, it has been reported that he hinted he already knew the commander while speaking to police as they tried to negotiate with him as he held the couple's young son hostage.

According to French daily newspaper, Liberation, Abballa said during the negotiations: 'He came to my home, now I've come to his.'

While another French newspaper, Le Monde reported the ISIS militant that Aballa may have had a grudge against his victims.

They added it suggests that Abballa had previous contact with Mr Salvaing who in the past had been stationed in Mantes-la-Jolie, where the killer lived.

French president Francois Hollande pays tribute to the slain couple in front of their coffins at a ceremony in Versaille

The coffins of the husband and wife were brought to the memorial ceremony and were draped in the French flag

Afterwards Hollande posthumously presented Mr Salvaing and Ms Schneider with the Legion d'Honneur, one of France's highest awards for bravery

Meanwhile, Ms Schneider also worked at the same police station as a police administrator.

It has also emerged that Abballa has already spent time in prison for 'criminal association in view to preparing terrorist attacks' after being accused of recruiting a network of jihadis of Pakistan and Afghanistan.

He was freed in September 2013 after serving most of his sentence on remand.

The new claims come as French President Francois Hollande attended a service in Versaille today for the slain couple.

The coffins of the husband and wife were draped in the French flag as Hollande delivered a tribute to them.

Afterwards he placed a medal on top of each casket as he posthumously awarded them both the Legion d'Honneur, one of France's highest awards for bravery.

After killing the couple, Abballa posted a 12 minute monologue on Facebook Live, showing the crime scene before he was killed when police stormed the house

Police stand guard outside the couple's house in Magnanville near Paris. Abballa reportedly said during hostage negotiations with police: 'He came to my home, now I've come to his.'

The attack has revived French concerns about the ISIS threat after the group targeted Paris last year killing 130 people.

Anti-terrorism investigators are questioning three suspects and are seeking to determine whether the attacker was working with a larger network.

During the video that Abballa posted on social media after the killings, he also chillingly hinted at an ISIS attack on the Euro 2016 football tournament, saying: ‘We're keeping another surprise for the Euros but I won’t say anything more.'

Police later raided Abballa's home and found a hit list on his computer which contained six names. Prosecutor Francois Molins said they included 'rappers, journalists, police officers and public personalities'.

Hundreds of policeman and members of the public take part in a march in honour of Mr Salvaing and Ms Schneider

The vigil to the slain police commander and his wife took place outside the French Interior Ministry in Paris

Meanwhile, yesterday Mr Hollande joined hundreds of public officials to pay homage to victims Mr Salvaing and Ms Schneider at the Interior Ministry in Paris.

There, he and French Prime Minister Manuel Valls warned the world faced a long war to defeat terrorism.

Mr Hollande said: '(Fighting terrorism is) a long war to wage not just in a few countries but in the whole world, everyone can be concerned.'