French authorities are now treating the fatal stabbing of a plain clothes police commander and his wife as a terror attack.
The 42 year old father of one, named locally as Jean Baptiste Salvaing, died from multiple stab wounds to his stomach on a street outside his home at Magnanville, some 55km west of Paris.
It is believed he was ambushed by a lone assailant who targeted him as he attempted to walk into his home.
The attacker then took the police commander's wife and young son hostage.
When police stormed the family home, the man's wife was found murdered.
However, his son was rescued unharmed.
French police sources said the killer had pledged allegiance to Islamic State of Iraq and the Levant (Isil).
Isil claimed responsibility for the killings in a statement released by the Amaq news agency, the group’s propaganda outlet, which it also used to announce that the Orlando massacre was perpetrated by an Isil fighter.
French police stressed that the attack was not linked in any way to Euro 16.
More than 100,000 Irish fans are currently in Paris for last night's clash with Sweden in Stade de France.
However, no Irish fans were staying anywhere near where the stabbing incident took place.
Initially, police had thought the attack was a local dispute which had tragically escalated.
However, it has now emerged that the attacker, named locally as Larossi Abballa (25), had close links to extremist Islamic groups.
Abballa lived close to the police commander's home.
Witnesses heard the assailant, described as a teenager or in his early 20s, shout “Allahu Akhbar”, Arabic for "God is great".
He served a two year prison sentence in 2013 for associating with groups planning a terror attack in France.
Abballa also had links to a recruitment network for terrorists operating in both Afghanistan and Pakistan.
The man was shot and killed at the scene by an elite French police unit who stormed the property after hostage negotiators failed to persuade him to surrender.
French officials expressed shock at the brutal nature of the attack and the fact the police commander was targetted at his home.
“The toll is a heavy one. This commander was killed by the individual - we (then) discovered the body of a woman. The assailant was killed.
Thankfully, a little boy was saved. He was in the house. He was saved by police officers,” a French Interior Ministry spokesman said.
One website with close links to Islamic State has issued a release apparently claiming responsibility for the knife attack.
The stabbing occurred in the outer Parisian suburb of Magnanville, some 55km west of the French capital.
It is also some 55km away from the centre of the Euro 16 celebrations at the Champs de Mars.
Explosions reported in the area are understood to be special flash-bang grenades used by police in storming properties during hostage situations.