The Federal Bureau of Investigation interviewed suspected marathon bomber Tamerlan Tsarnaev in 2011 at the request of the Russian government, but didn’t find evidence of suspicious activity and closed the case, an FBI official said Friday.
The fact that the FBI spoke with Mr. Tsarnaev, who was killed Friday morning in a firefight with authorities, is likely to become a focal point of the post mortem into how the attack was able to be carried out at the Boston Marathon. It also speaks to the challenge faced by authorities as terrorism morphs to some extent from the complex international plots of a decade ago to small-scale attacks carried out by individuals located within U.S.
U.S. counterterrorism policy has since 2001 focused largely on killing terrorists overseas or preventing them from getting into the U.S. But the Boston bombings show how the diffusion of terrorist tactics easily transcends borders. Countering small groups of individuals inside the U.S. can be a bedeviling assignment.