Sky News 
Sept 9, 2011
The White House believes home-grown terrorism is one of the greatest threats the US faces, ten years after the 9/11 attacks.
The biggest domestic terrorism investigation since 2001 has focused on the northern city of Minneapolis.
It is estimated up to 40 young men from the Somali community in Minneapolis have been radicalised and recruited to join the al Qaeda affiliate al Shabaab in Somalia.
There are also growing fears that the US faces the threat of an attack within its borders from young radicals carrying American passports.