Larossi Abballa

PARIS – A suspected Islamist attacker stabbed a French police commander to death outside his home and later killed his companion, a policewoman, in an attack claimed by ISIS and denounced by the government as “an abject act of terrorism.”

The assailant, a 25-year-old Frenchman, was jailed in 2013 for helping Islamist militants go to Pakistan and had been under security service surveillance, including wiretaps, at the time of the attack, police sources said.

The attacker filmed part of the assault live on the social network Facebook, according to David Thomson, a journalist specialized in radical Islamists. In his Facebook message, he linked the attack to the Euro 2016 soccer tournament now under way in France, saying: “The Euros will be a graveyard.”

The attacker, named by police and justice sources as Larossi Abballa, knifed the 42-year-old commander repeatedly in the stomach on Monday evening.=

He then barricaded himself inside the house in Magnanville, a suburb some 40 miles west of Paris, taking the man’s 36-year-old partner and their three-year-old son hostage.

Police commandos shot Abballa dead when they stormed the house after negotiations failed but they found the woman, a secretary at a police station in a nearby suburb, killed with a knife, a source close to the investigation said.

The boy was unharmed but in a state of shock.

“An abject act of terrorism was carried out yesterday in Magnanville,” Interior Minister Bernard Cazeneuve said after an emergency government meeting, before visiting Les Mureaux, where the police commander worked.

President Francois Hollande said the killings were “undeniably a terrorist act” and that the terrorist threat in France was very high.