From the beginning, there was no mystery about how she died. A tearful local woman informed the police earlier that evening that her son, aged just 15, had punched and kicked Alisha and thrown her, still alive, into the river. The boy’s girlfriend, 15, also a school-friend of the dead girl, had helped to roll her, half-conscious, down a concrete slope into the freezing water.

The two youngsters were on Thursday mis en examen (a formal accusation) for assassinat – assassination or pre-meditated murder. Investigators have pieced together, easily enough, the story of a teenage love triangle, social-media bullying and revenge porn. Neither of the alleged attackers, according to police, has shown much remorse.

All the usual clichés about violence and “savage youth” in the multi-racial banlieues (suburbs) are pouring out on social media and in right-wing websites. But the boy, who has admitted to the murder, is a computer geek, not a gang member. All three teenagers went to a private, technical school with a very high teacher-pupil ratio.

Argenteuil is an unlovely but comparatively quiet and hard-working part of the Paris banlieues. A century and a half ago, it was a pretty village on one of the great bends in the Seine west of the capital. Between 1871 and 1878, its residents included the great impressionist painter, Claude Monet.

Some of Monet’s most celebrated canvasses were painted in Argenteuil, including the famous image of a woman and child gathering poppies in a sloping meadow with grass and flowers up to their waist. I visited Argenteuil a few years ago to write a “before and after” feature  on Monet’s landscapes. The poppy slope is now covered in concrete blocks of flat from the 1970s.

Over that hill is another relatively peaceful Paris suburb, Conflans-Saint-Honorine. 

A 15-year-old girl admitted to police last week that she had lied about her presence at a civics lesson at a lycée in Conflans last October – lies which led to her teacher being beheaded. That story – an Islamist attack on a teacher wrongly accused of mocking Islam – was also partly a social media story.

What does the appalling murder of a 14-year-old girl by two of her schoolfriends tell us about France? 

It will become part of a litany of accusations by the right and far right that “violence is out of control” and that younger generations in the banlieues have become “ensauvagés” (turned into savages) by government softness, family neglect and – according to Marine Le Pen – “mass immigration”.

No matter if the facts don’t actually support the accusations. There certainly is endemic gang-warfare and a low value placed on life in some parts of the French banlieues and inner cities.

But suggestions that there is great wave of violent crime and murder, based on a number of high-profile incidents, do not stack up. The real peaks for murder in recent French history were the late 1940s and then the 1970s to mid-1990s. 

 Until the 1990’s France had over 1,600 murders a year. In most recent years, there have been around 850, rising to 970 in 2019.  In recent years – since Le Pen began her mantra –  violent crime (leaving aside sexual assaults) has fallen from 647,000 incidents in 2012 to 579,000 in 2018. 

 No matter also that the unusual – but very disturbing – facts of Alisha’s murder do not fit the preferred political narrative. None of the youngsters involved were gang members. The young man, who has not been named, is described by a neighbour as “never violent. In fact, the opposite.”

“This boy is kind of a geek. He spends most of his time in the apartment with his games console.”

His mother, evidently a woman with a moral conscience, alerted the police and spoke to media of her distress for the family of the dead girl as well as her distress for her son.

The sequence of events as outlined by Val d’Oise prosecutor Eric Corbeaux appears to be briefly as follows. The boy had a one week love affair with Alisha, the girl he murdered. He then became the boyfriend of the second girl, who was a friend of Alisha’s.

He objected to the two girls remaining friends. He hacked into Alisha’s phone and stole images of her in her underwear which he posted on the class Snapchat account. She protested to the school authorities. He was suspended.

A few days later, a fight broke out in a school corridor between the two girls. The second girl, who has not been named, was also suspended.

Girl number 2, recently turned 15, invited Alisha to meet her on the bank of the Seine to make it up. An ambush had already been planned with the boy by text over several days. When Alisha arrived, the boy stepped from behind a pillar and punched, tripped and kicked Alisha. He and his girlfriend rolled the semi-conscious girl into the river.

The boy went home and confessed to his mother, then fled to Paris with his girlfriend

Despite all the inevitable political claims and accusations, this seems to me not really to be a story about France, or the French banlieues.

Not much poppy-collecting by young people goes on in Argenteuil these days; but not much of it goes on anywhere else either.

This is a story about the social media age and internet age, when young people are invited to know a great deal but understand very little; to be grown up very young without, in some cases, growing up at all.

It’s about a casual acceptance of violence amongst some young people, which is present in France but not just in France. That, in itself, is worrying, whatever the crime figures might say.