The federal government is now examining the intelligence it had of Tamerlan Tsarnaev prior to the Boston marathon bombing in order to determine whether it could have acted to prevent the attack. Different spellings of the suspected bomber's name appear to have helped him avoid detection during recent travels to Russia.
Canadian police thwarted a terrorist attack on a US-Canada train by two men directed by Al Qaeda in Iran. Yes, Al Qaeda in Iran, say police.
What might have motivated suspects Tamerland and Dzhokhar Tsarnaev in the Boston bombings? Simplistic answers – say, Islamic militancy or immigrant anger – may not suffice. Yet knowing such motives may help everyone act to prevent such attacks.