ISLAMIC STATE

Islamic State claimed the attack. "God has enabled one of the caliphate's soldiers in city of Les Mureaux near Paris to stab to death the deputy police chief and his wife," an official broadcast on its Albayan Radio said.

If it is confirmed that the group was behind the killing, it would be the first militant strike on French soil since the multiple attacks on bars, restaurants, a concert hall and the national soccer stadium in Paris in November.

Details started to emerge on the profile of the attacker.

Abballa was born in the nearby town of Meulan and lived in Mantes-la-Jolie, where he had set up a fast food outlet in April, documents from the Versailles court showed.

He was given a three-year prison sentence in 2013 for helping Islamist militants go to Pakistan. His name appeared in a separate ongoing investigation into a man who went to Syria, but he was not considered a threat, a source close to the probesaid.

"He wanted to do jihad (holy war), that was clear," Marc Trevidic, a former anti-terrorism judge who was in charge of the 2013 investigation told Le Figaro newspaper. But he was seen ashaving a minor role in that case, he said.

Abballa had also been convicted three times on charges of aggravated theft and driving without a licence, a source closeto the investigation said.

"Many things are being analysed," a justice source said, including messages posted on social networks.

Thomson, an RFI radio journalist specialised in Islamic radicalism, wrote on his Twitter page that Abballa had filmed himself on Facebook live during the attack.

With the couple's boy behind him he said: "I don't know yet what I'm going to do with him," Thomson wrote.

Islamic State's claim of responsibility came after the Islamist militant group said it was responsible for the shooting that killed 49 people in a massacre at a gay nightclub in Orlando, Florida.