A solution to French teenage murderers?

Recently, a 14-year-old girl was found dead on in Paris, after being thrown into the Seine river. She was the victim of an ambush organized by two 15-year-old classmates. 

This sad event had a huge impact all over France with Social Media being designated as the obvious and largest culprit. 

From a distance and common-sense perspective though, this terrible tragedy puts most of the responsibility squarely on those parents who have long given up raising their off-springs. Instead, they’ve let school, media or technology assume their parental role. 

Under French law, the culprits, being minors, can’t be locked up for more than 20 years. Shouldn’t the parents face the music too and assume partial penal responsibility for the act of their kids by being locked up for a matching number of years, not to mention the assumption of civil liability arising in such situations. 

If the law was changed in that direction, behaviors would change drastically the concept of parenting and its responsibilities.