A man who claimed allegiance to the Islamic State stabbed a French policeman to death on Monday night.

The attacker then entered his home and held the man’s wife hostage, along with the couple’s three-year-old son.

The man’s wife was also found dead when police stormed the house, but the boy was rescued alive. The attacker was shot down by the police.

The attack in the Paris suburb of Magnanville was apparently carried out by a neighbour of the family.

Witnesses told investigators the attacker may have shouted “Allahu akbar” (God is greatest) as he stabbed the police officer repeatedly outside his home before holding the woman and the boy inside, says the Guardian.

The police officer who died was named in the French media as Jean-Baptiste Salvaing, 42, and was reportedly returning home, out of uniform.

The attacker was a neighbour and authorities tried to negotiate with him before storming the house, according to French media reports.

Officers found the woman’s body when they stormed the building and the attacker was killed during the raid, said interior ministry spokesman Pierre-Henry Brandet said.

The boy was “in shock but unharmed” and receiving medical attention, a prosecutor added.

New details reveal that the attacker named in the French press as 25-year-old Larossi Abballa, had been sentenced in 2013 for taking part in a jihadist organisation with links to Pakistan.

He was sentenced to three years, six months of which were suspended for ‘criminal association with the aim of preparing terrorist acts,’ following a trial with seven other defendants.

Abballa had claimed allegiance to ISIS while the terror group’s Amaq news agency said the attacker was an ‘Islamic State fighter’ and claimed responsibility for the killings.

New details in the case released by “Le Figaro” newspaper mention that before police raid the killer posted on his Facebook account photos of the dead bodies of the couple he killed. “Euro will turn into a cemetery,” he posted indicating that police officers, security guards, journalists and rapists are targets. After killing the couple, he wrote on Facebook: “I have not decided yet what should I do with the child!”

The French journalist and jihadhist expert, David Thomson, reported that Abballa had used Facebook live to post images of the attack. Thomson reported that while the attacker filmed himself, the three-year-old boy was behind him on the sofa. The attacker said “I don’t know yet what I’m going to do with him.”