The attackers from Charlie Hebdo were trained military experts

According to a man from military invited at television, the attackers were military trained.
Their shooting was very accurate and grouped.
They moved at ease in a formation similar with one of special forces.
Anyone can see that they were not shy to leave their car and shoot the police officers.
Maybe a less trained and a less experienced attacker would hide behind the car, or he would spray with bullets.
So there were not a lone wolfs, some islamists from France upset from the insults of Charlie Hebdo, who bought some pistols and attacked randomly people in the newspaper headquarters.
These people were professionals who received intelligence from other conspirators .
(They missed first time the address, this means that they didn't made themselves the surveillance, so there were also other conspirators who gathered information)
They swiftly  executed their plan and escaped, maybe toward some harbour, to leave the country a board of a ship.
It was a conspiracy who used spies,cars and houses from the French Muslim community.
This is more interesting to investigate.
I wonder how this was not detected by France intelligence.