June 2016 Magnanville stabbing
The attacker is identified as Larossi Abballa, a 25-year-old man who, according to police sources, was a neighbor of the murdered couple. Abballa was one of eight men convicted in Paris in 2013 for making plans to travel to Pakistan for terrorist training, and then to commit terrorists acts. Abballa was sentenced to three years in prison. He was released after the trial as six months of the sentence was suspended, and he had already spent two years in jail awaiting trial.
Sources: The New York Times The Telegraph