The killing of a police captain and his partner was part of a string of deadly Islamist terrorist attacks in 2015 and 2016 that scarred France.
A French-Moroccan man was convicted on Wednesday on charges of complicity in the 2016 murders of an off-duty police officer and his partner at their home near Paris, part of a wave of deadly Islamist terrorist attacks that deeply shocked France.
A criminal court in Paris found that the man, Mohamed Lamine Aberouz, 30, helped stage the attack that killed the officer, Jean-Baptiste Salvaing, 42, a police captain, and his partner, Jessica Schneider, 36, an administrative worker at a police station.
The court found him guilty of multiple charges, mainly complicity in the murders and of being part of a terrorist conspiracy, and sentenced him to life in prison, with the possibility of parole only after 22 years. Mr. Aberouz had always denied playing any role in the killings.
Mr. Salvaing and Ms. Schneider were murdered at their home in Magnanville, a small town northwest of the French capital, on the evening of June 13, 2016, by Larossi Abballa, 25, an Islamist extremist who cut Ms. Schneider’s throat inside the couple’s home and stabbed Mr. Salvaing on the street in front of it before taking their 3-year-old son hostage for several hours.
Mr. Abballa then filmed a violent, 13-minute rant that he broadcast live on Facebook, declaring allegiance to the Islamic State and calling for the murder of police officers, journalists and other targets before he was shot and killed by the police.
The brutal killing of the couple was part of a string of deadly terrorist attacks that inflicted lasting trauma on France, including the November 2015 shootings and bombings, carried out by an Islamic State team, that killed 130 people in and near Paris, and the July 2016 attack in which an assailant plowed a truck into a Bastille Day crowd in Nice, leaving 86 people dead.
But the murders were especially disturbing for French police officers, who were shocked that one of their own had been targeted in his own home. In the weeks that followed the attack, France eased its gun rules to allow off-duty police officers to carry their sidearms.
Mr. Aberouz, a childhood friend of Mr. Abballa, was not directly charged with the couple’s murder, which was quickly claimed by the Islamic State, but prosecutors said he shared Mr. Abballa’s extremist views and accused him of helping stage the attack.
Their case hinged upon a trace of Mr. Aberouz’s DNA that was found on the couple’s laptop — proof, they argued, that Mr. Aberouz was at the house at the time of the murder and had fled before the police arrived.
In a rare interview before the verdict, Josiane Schneider, Ms. Schneider’s mother, told French news outlets on Tuesday that she was convinced her daughter could not have been subdued by a single assailant.
“My firm belief is that there has to be a second person and, for me, it’s him,” she said of Mr. Aberouz.
Although Mr. Aberouz acknowledged at trial that he adhered to a strict interpretation of Islam, he denied having played any role in the killings, arguing that he was at a mosque in a nearby town that night.
At trial, his defense lawyers said that Mr. Aberouz’s DNA could have been brought into the house by Mr. Abballa — similar traces were found in his car — and they said prosecutors had failed to demonstrate what role Mr. Aberouz played in the attack.
Charaf-Din Aberouz, Mr. Aberouz’s older brother, regarded by French intelligence services as Mr. Abballa’s religious mentor, was charged during the yearslong investigation, but he had an alibi for the night of the murder and the case against him was ultimately dropped, leaving only Mr. Aberouz to stand trial.
Mr. Abballa had been identified by French intelligence services as a threat, and his case was emblematic of the struggle faced by French authorities as they tried to identify and apprehend lone extremists who were inspired by the Islamic State or other groups but had given little forewarning of a plan to act.
He had been convicted in 2013 for his role in a network suspected of recruiting for Al Qaeda, and he was placed under surveillance after his release from prison that same year. But the surveillance did not bear any fruit and was terminated at the end of 2015 — just months before the attack in Magnanville.