Cherif Kouachi, 32, and his brother Said, 34, accused of carrying out the massacre at the Charlie Hebdo office in Paris, managed to slip under the radar despite them being on counterterrorism agencies' radar for years before Wednesday’s attack.
French intelligence was aware that Said Kouachi had travelled to Yemen in 2011 to receive training from an Al-Qaeda's affiliate in small arms combat and marksmanship.
Cherif had earlier been sentenced to 3 years of jail for his connection with a militant cell that had been getting foreign fighters to join the Al Qaeda in Iraq.
The brothers had been in the US terrorism database and on the US no-fly list "for years", media reports said.
An AFP report says that Cherif's history with jihadist networks is even better documented and dates back over a decade to his days as part of the "Butte-Chaumont network", named after a park in the 19th arrondissement of Paris where its members lived.
The group helped transport radical Muslims to Iraq to join Al-Qaeda's fight against US forces.
Cherif, was arrested when he was 22 just as he was about to fly to Syria in 2005 and then to Iraq.
At his trial in 2008, Kaouchi said he was inspired by the abuse of detainees by US troops at Baghdad's Abu Ghraib prison. He told the court he worked at a supermarket and his main interest was rap music.
Cherif was sentenced to 3 years in prison, though half of it was suspended. He was involved in another plot in May 2010 in a failed prison break for Algerian Islamist Smain Ait Ali Belkacem.
On Wednesday Cherif and Said gunned down 12 people at the office of satirical magazine Charlie Hebdo.
Image: A picture of Said Kouachi released by the French police
