Washington ( CNN ) -- When Russia asked the FBI in 2011 to check out Tamerlan Tsarnaev because of his shift toward increasing Islamic extremism , the bureau interviewed him and his family as part of a review that found no ties to terrorism . Two years later , Tsarnaev , 26 , and his younger brother allegedly set off two bombs at the Boston Marathon that killed three people , then killed a university police officer and sparked a manhunt that paralyzed the city last week . Now members of Congress want to know how someone who was brought to the attention of authorities and who exhibited increasingly radical leanings never came under further monitoring or questioning . Graham backs off FBI criticism over bombing suspect . Sen. Dianne Feinstein announced Monday that the Senate Intelligence Committee she heads will look into the FBI 's handling of Tsarnaev . The hearing with FBI intelligence officials , expected to be closed to the public and media , could happen as soon as Tuesday , said Feinstein , D-California . A look at Tamerlan 's past . An aide to the House Homeland Security Committee said its chairman , Republican Rep. Mike McCaul of Texas , also intended for the panel to examine the issue . The Tsarnaev case raised questions about the efficiency of overall security efforts , particularly involving people brought to the attention of federal authorities . Tsarnaev , who died after a shootout with police on Thursday night , was an immigrant from the volatile Caucasus region of southwest Russia who had legal residence in the United States and sought last year to become fully naturalized , like his brother Dzhokhar , 19 . Bombing suspect 's wife 'very distraught ' However , the Department of Homeland Security rejected the citizenship request due to his past questioning by the FBI before a trip to Russia . An FBI statement said a foreign government -- later identified by legislators as Russia -- asked for information on Tsarnaev `` was based on information that he 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 said , it `` checked U.S. government databases and other information to look for such things as derogatory telephone communications , possible use of online sites associated with the promotion of radical activity , associations with other persons of interest , travel history and plans , and education history . '' `` The FBI also interviewed Tamerlan Tsarnaev and family members , '' it said in the statement on Friday . `` The FBI did not find any terrorism activity , domestic or foreign , and those results were provided to the foreign government in the summer of 2011 . '' In addition , the FBI `` requested but did not receive more specific or additional information from the foreign government , '' its statement said . That failed to satisfy Feinstein and other legislators . `` I have asked the staff director of Intelligence this morning to set a hearing , particularly with FBI intelligence , '' Feinstein told CNN on Monday , adding she hoped for answers about what Tsarnaev did during the trip . What was Tamerlan Tsarnaev doing in Russia ? `` And when he came back to this country , why did n't it ring a bell with the FBI intelligence unit that he should be checked out and vetted again ? '' she asked . Feinstein also noted that Homeland Security officials later denied Tsarnaev 's application for citizenship , raising another question about who knew what about him . The purpose of the hearing was `` not to criticize , because I am a big fan of the FBI 's , but to go back and see that we plug loopholes , '' Feinstein said . Timeline : A look at Tamerlan Tsarnaev 's past . Tsarnaev , who 's ethnically Chechen but came to the United States from Kyrgyzstan , spent six months in Russia , causing some legislators and analysts to speculate he may have received training during the trip . Conservative Sen. Lindsey Graham , who said Sunday the FBI may have dropped the ball in its investigation of Tsarnaev , began easing off that claim on Monday . The South Carolina Republican confirmed he talked to the assistant director of the FBI and learned how the bureau interviewed Tsarnaev , his parents and classmates in 2011 . `` They put his name through the system and they sent back this information to the Russians and said , 'Do you have anything else ? ' And they never got a reply back , '' Graham said . Graham also noted that Tsarnaev was n't flagged upon returning from Russia because of an apparent misspelling of his name by the Russian airline Aeroflot . `` It did n't get into the system because of a misspelling , '' Graham said . `` Now whether or not he intentionally changed his name or Aeroflot just got the spelling wrong , I do n't know . That 's to be determined . '' As for apparent warning signs that occurred within the last year , such as YouTube postings of radical Islamists , Graham said the FBI told him `` they have limitations on what they can do . '' Dead Boston bomb suspect posted video of jihadist , analysis shows . `` So maybe it 's the system failed , did n't provide the FBI with the tools , or maybe they did n't use it properly , '' he added . `` That 's why maybe we need to find out what happened . '' His comments sounded similar to those made by House Intelligence Committee Chairman Mike Rogers , who defended the FBI on Sunday . Rogers told NBC the agency `` did their due diligence '' but Russian authorities `` stopped cooperating '' when the United States sought further clarification . Rogers also said he believed Tsarnaev may have traveled overseas using an alias . CNN law enforcement analyst Tom Fuentes , a former FBI official , said there was little the bureau could do once Russia failed to respond to its request for further details . 5 key questions . `` If they do n't give you more , then everything that can be done has been done unless you know that there should be more to the story , '' Fuentes said . He detailed how the FBI employs what amounts to `` triage '' to deal with what he said were tens of thousands of similar inquiries a year that require some level of bureau investigation . `` If you are getting this from a hot place like Afghanistan or the tribal area of Pakistan or places where we have had specific training camps and people deployed on purpose to come and attack us , then that is the highest priority , '' he said . `` And even there , many of the people that go back and forth are visiting family . I mean , they are not always going back to be trained to be terrorists or always going back for refresher courses on terrorism . '' Regarding Russia , Fuentes noted the ongoing conflict with Chechen separatists that may have caused Moscow 's request for information on Tsarnaev . Lohr : What we know about Chechnya . `` That 's been an ongoing fight , but it 's been localized , '' he said , adding that he could n't recall a case in which a Chechen trained at home came to attack the United States . However , Fuentes noted that al Qaeda had sent people to the Caucasus region for training that included bomb building . Now U.S. investigators need to find out if the Tsarnaevs `` had connections , were they deployed by a bigger group , and are there other terrorists in the United States , '' Fuentes said . `` Are there other explosive devices hidden somewhere or booby traps created , a cache of weapons ? '' he wondered . `` That 'll be the task . '' de Waal : Suspects ' culture of migration and machismo . CNN 's Ashley Killough contributed to this report .
Former official : FBI uses `` triage '' approach in checking out possible terror links . Comment: The FBI interviewed Tamerlan Tsarnaev before he traveled to Russia last year . Some legislators question why Tsarnaev was n't questioned again on his return .