WASHINGTON — Federal law enforcement and intelligence agencies “generally shared information and followed procedures appropriately” in their investigation of Tamerlan Tsarnaev and his brother, Dzhokhar, in the years leading up to the Boston Marathon bombing, but they should have more closely scrutinized Tamerlan when he returned to the United States from Dagestan in 2012, according to a report by the inspector general for the intelligence community that was released Thursday.
According to the report, the Russian government withheld some information about Tamerlan Tsarnaev, who was killed in a shootout with the police after the bombing last April, despite requests from the FBI. The agent who conducted the FBI’s initial investigation of Tsarnaev in 2011, the report said, could have done a more thorough assessment.
“With respect to the F.B.I.’s pre-bombing investigation, we concluded that the F.B.I. made investigative judgments based on information known at the time and that were within the legal framework governing its ability to gather intelligence and conduct investigations,” it said. “We believe it is impossible to know what would have happened had different judgments been made.”
The report was released by the Office of the Intelligence Community Inspector General, which oversees 17 agencies. The inspectors general for the Justice Department, the Homeland Security Department and the CIA also contributed to it.
Much of the report focused on how the agencies handled information about Tsarnaev that was provided to the FBI by the Russian government in March 2011.
According to the FBI, Russian officials reported that Tsarnaev “was a follower of radical Islam and a strong believer” and that he “had changed drastically since 2010 as he prepared to leave the United States for travel to the country’s region to join unspecified underground groups.”
In response, the FBI conducted an assessment of Tsarnaev, the least invasive of its three types of investigations, and found nothing to substantiate the information. The Russians declined at least two requests from the FBI for additional information they may have had on Tsarnaev.
But after the bombings, the Russians shared with the FBI information about a phone conversation they had intercepted between Tsarnaev and his mother in which the two discussed jihad.
In the course of its investigation, the inspector general’s office found “no basis to make broad recommendations for changes in information handling or sharing,” but it said there were “some areas in which existing policies or practices could be clarified or improved.”
In a letter to the inspectors general, the FBI director, James B. Comey, said the review “confirmed that when Russian authorities provided limited information to the F.B.I. about Tamerlan Tsarnaev and his mother in 2011, the F.B.I. acted appropriately.”