Boston Marathon 2013 bombing suspect Tamerlan Tsarnaev was placed on a counterterrorism list in late 2011.
The CIA requested that Tamerlan Tsarnaev's name be put on a list after it was contacted by Russian authorities because they were concerned he had become too radical. The CIA asked that Tamerlan be put on the Terrorist Identities Datamart Environment, or TIDE, database which feeds several government watch lists, including the FBI's Terrorist Screening Database and the TSA's "no-fly" list.
The FBI was alerted even earlier than the CIA by Russian authorities about Tamerlan. The FBI conducted a preliminary investigation, but found no evidence of any threat. The FBI did place Tamerlan on another database, operated by US Customs and Border Protection, called TECS in March 2011.
Maybe part of the problem was the FBI and CIA were too busy entrapping young 'terrorists' on Facebook to catch the real ones. What we shouldn't do though is listen to politicians like Bloomberg who think that the government should have even more control over our lives.