The network said the FBI opened an investigation of Tsarnaev that month conducted by a joint task force of federal, state and local authorities. Tsarnaev was interviewed in person, and a memo was sent to the Customs and Border Protection database called TECS that would trigger an alert whenever he left or re-entered the United States.

In September 2011, the FSB sent a cable to the CIA, restating the warnings of the first memo. NBC News quoted sources close to the congressional investigation as saying a second note about Tsarnaev was entered into the TECS system the next month, but spelled his name „Tsarnayev.“