The FBI had received a nearly identical request from the Russian government six months earlier, prompting a review of Tsarnaev's activities that turned up nothing improper, a federal law enforcement official said.
Tsarnaev, 26, was killed in a confrontation with police early Friday, hours after photos of him and his brother, Dhokhar Tsarnaev, were circulated as suspects in the Boston attacks. Dzhokhar Tsarnaev, now recovering from a neck wound, was charged Monday and faces a possible death sentence if convicted.
Tsarnaev's inclusion on the Terrorist Identities Datamart Environment (TIDE), a list of more than 500,000 names, is raising questions from lawmakers about why federal authorities did not continue to monitor Tamerlan Tsarnaev who, following the FBI inquiry, left for a six-month trip to Russia on Jan. 12, 2012. Homeland Security Secretary Janet Napolitano told a Senate panel this week the watch system alerted authorities of his departure. By the time he returned, she said, the FBI investigation had been closed.
Reps. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee, and Pete King, R-N.Y., have called on the FBI and the Department of Homeland Security to provide more information.
The law enforcement official, who is not authorized to comment publicly, said the CIA was aware of the FBI review and referred the new request back to the FBI. The CIA may not conduct intelligence operations on U.S. soil.
The FBI again contacted its Russian counterparts, asking if they had additional information on Tamerlan Tsarnaev. Russian authorities, the official said, never responded.
In Boston, Dhokhar Tsarnaev has told federal investigators that the deadly attacks were launched last week without a rehearsal.
The federal law enforcement official said Dhokhar Tsarnaev said he and his brother did not test fire the pressure-cooker devices before planting them near the crowded finish line of the race, where three people were killed and 264 injured.
Earlier Wednesday, their father said he and his wife would travel to the United States from Dagestan on Thursday to assist with the investigation.
FBI agents traveled to the Russian republic to interview Anzor Tsarnaev and his wife, Zubeidat Tsarnaeva, to try to determine how their sons became radicalized.
She took a taxi to the offices of the Russian security services, or FSB, in Makhachkala, the capital of Dagestan, where she was interviewed by U.S. and Russian officials. But Anzor Tsarnaev was not questioned, telling officials he felt ill.
Zubeidat Tsarnaev, mother of Boston bombing suspects Tamerlan and Dzhokhar Tsarnaev, walks near her home in Makhachkala, Dagestan, southern Russia, on Tuesday. She was questioned in Dagestan by the FBI and other officials on Tuesday.(Photo: Ilkham Katsuyev, AP)
He later told the Russian news agency RIA Novosti that the couple would travel to the United States the next day to offer assistance.
A lawyer for the family said, however, that the family had not finalized their plans.
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Investigators are looking into whether Tamerlan Tsarnaev, who spent six months in Russia's Caucasus in 2012, was influenced by the religious extremists who have waged an insurgency against Russian security services in the area for years. The brothers have roots in Dagestan and neighboring Chechnya, but neither spent much time in either place before the family moved to the United States a decade ago.
Shortly before he...