As the investigation proceeds, new findings have come into the picture about the infamous Boston bombings. The security agencies have found that US authorities had earlier put suspect Tamerlan Tsarnaev in two different watch lists after Russian FSB reported their American counterparts about his activities way back in 2011. It is now a matter of serious concern if the US security agencies have failed to prevent the attack in spite of having prior warnings from the Russians.

Russian officials contacted the Federal Bureau of Investigation in March 2011, then reached out to the Central Intelligence Agency in September of that year, citing concerns Mr. Tsarnaev might have been associating with extremists. The FBI sources said , it interviewed Mr. Tsarnaev and conducted a threat assessment, but found nothing "derogatory" that could prompt further investigation about his later activities.

It is also reported that  at the request of the CIA, Tsarnaev was added to a broad database called Terrorist Identities Datamart Environment, which holds hundreds of thousands of names flagged by federal security agencies.

(Jyotishman)