Homegrown terror difficult to prevent

US and French intelligence officials are leaning toward an assessment that the Paris terror attacks were inspired by al-Qaida but not directly supervised by the group, a view that would put the violence in a category of homegrown incidents that are extremely difficult to detect and thwart.

Although one of the two brothers who carried out the attack at the Charlie Hebdo is believed to have traveled briefly to Yemen in 2011, where he met an al-Qaida leader, US intelligence officials are not convinced that the Paris attacks were directed from abroad, despite a claim of responsibility by al-Qaida's Yemen affiliate. The claim seems hastily put together and "opportunistic", said two senior officials who declined to be named.

Investigators also are not convinced that Amedy Coulibaly, who killed five people in Paris in separate incidents, coordinated in advance with Cherif and Said Kouachi, who killed 12 in the attack on the Charlie Hebdo.