U.S. officials are saying Tamerlan Tsarnaev’s name was added to a U.S. government terrorism database about 18 months before the Boston Marathon bombings.
In the fall of 2011, Russia contacted the CIA with concerns about Tamerlan Tsarnaev. Two officials say the CIA added Tsnaraev's name to a terrorism database and that the FBI conducted an investigation but did not find he had any terror connections.
On Wednesday, U.S. officials also said that the pressure-cooker bombs the Tsarnaev brothers used were triggered by a remote detonator of the kind used in remote-control toys.
Investigators found pieces of the remote-control equipment among the debris and were analyzing them.
The officials spoke on condition of anonymity because they were not authorized to speak publicly about the investigation.
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