- Mohamed Lamine Aberouz, 24, has been linked to Larossi Abballa, the Islamic State extremist who claimed the June 2016 attack in a live video from the murder scene before being killed by police in a shootout, the sources added.
French police charged a man on Monday in connection with the jihadist murder of a police couple after his DNA was matched to traces found in their home near Paris, legal sources said.
Mohamed Lamine Aberouz, 24, has been linked to Larossi Abballa, the Islamic State extremist who claimed the June 2016 attack in a live video from the murder scene before being killed by police in a shootout, the sources added.
Aberouz, who was not on a terrorism watchlist but was known to be radicalised, was arrested in the western Paris suburb of Les Mureaux. He was charged with being an accomplice to murder in connection with a terrorist act and remanded in custody.
His brother has already been charged with providing logistical assistance to Abballa, whose chilling attack -- one in a string of assaults in France since January 2015 -- caused shock in police ranks.
Abballa stabbed police captain Jean-Baptiste Salvaing to death outside his home in Magnanville, 60 kilometres west of Paris, and then slit the throat of his companion Jessica Schneider in front of the couple's three-year-old son.
In a Facebook Live video from the scene, he called for further terror attacks.
Aberouz was already investigated over a foiled attack by a group of female jihadists who tried to set set fire to a car containing gas canisters near Notre-Dame Cathedral in Paris in September 2016.
Charged with failing to report that plot, he spent four months in preventive custody before being released in January.
Investigators believe that a notorious French IS member, Rachid Kassim, directed both attacks from the Middle East, using the encrypted Telegram app.
Kassim is believed to have been killed in a coalition air strike near the Iraqi city of Mosul in February.