U.S. Sen. Saxby Chambliss (File Photo)
WASHINGTON — U.S. lawmakers grilled top security officials on Tuesday about the handling of the Boston Marathon bombing investigation and why one of the suspects flagged as a possible Islamist radical was not tracked more closely.
FBI officials briefed members of Congress behind closed doors in Washington about the investigation into the April 15 blasts that killed three people and injured 264 others.
Authorities say the ethnic Chechen brothers, who immigrated to the United States a decade ago from the predominantly Muslim region of Dagestan in Russia's Caucasus, detonated two bombs made from pressure cookers near the finish line of the iconic foot race.
Tamerlan Tsarnaev, 26, was killed in a shootout with police and his younger brother Dzhokhar Tsarnaev, 19, lies wounded in a Boston hospital charged with using weapons of mass destruction.
Investigators have focused on a trip to Dagestan last year by Tamerlan Tsarnaev and whether he became involved with or was influenced by Chechen separatists or Islamist extremists there.
Russian authorities flagged him as a possible Islamist extremist in 2011. The FBI interviewed him in Massachusetts but found no serious reason for alarm. Some lawmakers have questioned if more could have been done at the time.
Senators said after a briefing by FBI Deputy Director Sean Joyce and other officials that there may have been a breakdown in communication that kept authorities from tracking his apparent radicalization.
Senator Saxby Chambliss of Georgia, the ranking Republican on the Senate intelligence committee, said the briefing raised questions about the flow of information among law enforcement and intelligence agencies.
"I think there has been some stonewalls, and some stovepipes reconstructed, that were probably unintentional, but we've got to review that issue again, and make sure there is the free flow of information," he said.
"I can't say the FBI dropped the ball. I don't see anybody yet that dropped the ball," he said. "That may develop."
The senators said there was tough questioning during the briefing.
"We had a full discussion back and forth over the process that's followed, and we need to keep at that, and we need to see if there are any loopholes in it, and that we fix those loopholes," said Democratic Senator Dianne Feinstein of California, who chairs the committee.
Lawmakers said they were unable to confirm an NBC report that the Tsarnaev brothers had been motivated by the U.S. wars in Afghanistan and Iraq or speculation that they had used fireworks to provide the explosives used in their bombs.