For anyone trying to recruit people to the cause of radical Islam, a French jail would be an ideal place to start.

As many as 60% of France's 70,000 prisoners have Muslim origins, and their backgrounds and criminal records make many ripe for radicalisation.

"They have been broken by educational failure, family breakdown, and unemployment. They are very fragile people," says Missoum Chaoui, a Paris Muslim leader who has worked as prison chaplain for 17 years.

Among the French criminals believed to have turned to extremism while behind bars is Amedy Coulibaly, a man of Malian descent who shot dead a policewoman and four Jews in two of last month's three deadly attacks in the Paris area.

Coulibaly forged the links that would turn him into a jihadist while in jail for robbery in 2005.

At Fleury-Merogis prison, he later told police interrogators, he met one of France's most dangerous inmates, Djamel Beghal.

An al-Qaeda-linked militant, Beghal was then serving a 10-year sentence in Europe's largest prison for a plot to bomb the US embassy in Paris. Although Beghal was being kept in isolation, Coulibaly says he was able to befriend him.

Coulibaly was also introduced to another follower of Beghal, Cherif Kouachi. The three then met after their release.

Eventually Coulibaly, Cherif Kouachi and his brother Said co-ordinated the attacks that killed 17 people in January. The Kouachi brothers shot dead 12 people at Charlie Hebdo magazine, shouting "Allahu Akhbar".

Online recruitment

The justice ministry has warned against using Coulibaly's story to portray French jails as breeding grounds for militants. "No-one can really tell whether he was radicalised in prison or outside," ministry spokesman Pierre Rance says.

Mr Rance also points out that, of 167 people detained in France on terror charges and regarded as radical Islamists, only 15% had been incarcerated before.

Clearly, extremists gain more recruits through personal contact or online than in prisons.

Nevertheless, Justice Minister Christiane Taubira admitted after the attacks in January that radicalisation in detention was a "major issue".

It is also far from new. Over the past 20 years, a number of major attacks have been blamed on one-time petty criminals who found religion in French prisons.

http://www.bbc.com/news/world-europe-31129398