FBI seeks images in Boston Marathon bomb probe; new details emerge on explosives - CBS News
Richard Barrett, the former U.N. coordinator for an al Qaeda and Taliban monitoring team who has also worked for British intelligence, said the relatively small size of the devices in Boston and the timing of the blasts suggest a domestic attack rather than an al Qaeda-inspired one.
"This happened on Patriots' Day — it is also the day Americans are supposed to have their taxes in — and Boston is quite a symbolic city," said Barrett, now senior director at the Qatar International Academy for Security Studies.