A New York Police officer stands guard at the corner of the New York Stock Exchange in New York April 19, 2013, as part of heightened security in the wake of the Boston Marathon bombing. 
 
 WASHINGTON (Reuters) - The FBI interviewed suspected Boston Marathon bomber Tamerlan Tsarnaev in early 2011, it said in a statement late Friday, following a tip from a foreign government that he was "a follower of radical Islam" and was preparing to leave the United States to join underground organizations. 
 
 The FBI said its interview two years ago of Tsarnaev and his family, along with checks of travel records, Internet activity and personal associations, "did not find any terrorism activity" at the time. 
 
 But the revelation is the first evidence that the Tsarnaev family came to U.S. security officials' attention after they emigrated to the United States about a decade ago, and it could raise questions about whether the government missed potential warning signs about the behavior of two brothers. 
 
 Tamerlan Tsarnaev, 26, died overnight in Boston in a shootout with police. His younger brother, Dzhokhar, 19, was taken into custody on Friday evening in the Boston suburb of Watertown after a dramatic, day-long manhunt, Boston police said. 
 
 The FBI statement did not disclose which foreign government asked it for information about the brothers and their family. But Tamerlan was widely reported to have made a trip to Russia last year. 
 
 The brothers and their family were ethnic Chechens, whose small republic's attempts at independence following the collapse of the Soviet Union were brutally crushed by Moscow. Both brothers, however, were born in the Central Asian state of Kyrgyzstan, the FBI statement said, and Dzhokhar was a naturalized U.S. citizen. 
 
 The revelation that the elder Tsarnaev was on U.S. law enforcement authorities' radar screens seemed likely to raise uncomfortable questions for the Obama administration about whether it could have done anything to detect and stop the plot. 
 
 "It's new information to me and it's very disturbing that he's on the FBI radar screen," Rep. Michael McCaul, Texas Republican and chairman of the House Homeland Security Committee, said on CNN late Friday. 
 
 It is not known when the Boston Marathon bombings were planned, or whether there were clues that could have allowed authorities to pre-empt it. 
 
 National security and law enforcement authorities said on earlier Friday that they had not turned up any evidence that the Tsarnaevs had contacts with al Qaeda or other militants overseas. 
 
 Rep. Peter King, New York Republican and member of the House intelligence committee, said in a statement that there "was no federal intelligence or chatter prior to the marathon bombings," a reference to militant communications often picked up in advance of an impending attack. 
 
 The U.S. officials said they were leaning toward the theory that the bombings were motivated by Islamic extremism, although that remained unproven. 
 
 WERE THE TSARNAEVS WORKING WITH OTHERS? 
 
 Violent plots involving a single individual or small groups who self-radicalize and have minimal dealings with other militants can be extremely difficult to detect in advance, according to U.S. counterterrorism officials and private experts. 
 
 The revelation about the FBI contacts with the elder Tsarnaev came as U.S. officials told Reuters that investigators are scouring government data banks to determine if spy and police agencies missed potential clues that might have alerted them to the two brothers. 
 
 Another top priority for investigators is to determine whether the brothers had any confederates either inside the United States or overseas, one U.S. official said. This official and others spoke on condition of anonymity to discuss an ongoing investigation. 
 
 Three people were taken into custody for questioning in New Bedford, Massachusetts, police said on Friday. Two men and a woman are being questioned by the FBI "on the assumption there is an affiliation with" Dzhokhar Tsarnaev, Lieutenant Robert Richard of the New Bedford Police said. 
 
 One official said the possibility that the U.S. government had information that should have raised questions about the Tsarnaev brothers before the attack could not be ruled out. Other officials said they were unaware that such material had turned up. 
 
 In several recent cases, U.S. intelligence and law enforcement agencies failed to put together clues that, in hindsight, might have led them to pre-empt a plot. 
 
 In 2009, U.S. Army Maj. Nidal Hassan killed 13 people and wounded another 32 at Fort Hood, Texas. Prior to the shooting spree, Hassan had email contacts with Anwar al-Awlaki, the U.S.-born cleric and leader of al Qaida's affiliate in Yemen who was later killed in a U.S. drone strike. 
 
 U.S. authorities had investigated Hassan's emails, but concluded they posed no threat of violence. 
 
 The father of Umar Farouk Abdulmutallab, the so-called "underwear bomber" who tried to bring down a U.S. jetliner over Detroit on Christmas Day 2009, reported suspicions about his son's activities to the U.S. Embassy in Nigeria. But Abdulmutallab's U.S. visa was never revoked. 
 
 A report by the Senate intelligence committee heavily criticized U.S. intelligence agencies for failing to act on available information in that case. 
 
 But Brian Jenkins, a respected terrorism expert at the RAND Corp., dismissed the idea that the Boston bombings represented an intelligence failure. 
 
 People will inevitably ask, "did we miss something in intelligence?" said Jenkins, speaking before the news of the 2011 FBI interview with Tamerlan Tsarnaev become public. 
 
 "Some people will label it an 'intelligence failure.' But that's because people have come to expect 100 percent security," he said. 
 
 (Additional reporting by Patrick Temple-West; Editing by Paul Simao and Stacey Joyce) ||||| Exclusive 
 
 Dzhokhar Tsarnaev has told investigators that he and his brother were influenced by the Internet sermons of the notorious preacher Anwar al-Awlaki, Daniel Klaidman reports. Plus: the feds now know who “Misha” is. 
 
 As investigators sift through the lives of Tamerlan and Dzhokhar Tsarnaev trying to understand their radicalization and descent into violence, one clue almost seemed expected. Two U.S. officials tell The Daily Beast that, during his hospital room interrogation, Dzhokhar told FBI agents that he and his brother were influenced by the Internet sermons of Anwar al-Awlaki, the American-born preacher who was killed in a U.S. drone strike in Yemen in September 2011. The charismatic cleric was seen by the Obama administration as a uniquely dangerous terrorist because of his sermons (delivered in fluent, American-inflected English), his intuitive grasp of U.S. culture, and a burning desire to strike his birth nation. 
 
 It is unclear the extent to which—if at all—Awlaki’s preachings inspired the brothers to commit terrorism. Indeed, whatever his role, it is likely only a small piece of a complicated, multilayered puzzle. In recent days, there has been speculation that another piece of that puzzle could be a man known simply as “Misha,” whom relatives of the brothers have said held sway over Tamerlan. “This person just took his brain,” Tsarnaev’s uncle, Ruslan Tsarni, told CNN. “He just brainwashed him completely.” Now, The Daily Beast has learned that federal law enforcement officials have identified Misha—although one source suggested it might be a less important part of the case than previously thought. 
 
 As for Awlaki, while we don’t know the extent of his influence on the brothers, we do know that there is a long trail of hardened terrorists who have acknowledged coming under his sway. Among them are Faisal Shahzad, the Pakistani-American who attempted to set off a car bomb in Times Square in May 2010, and Nidal Malik Hasan, the U.S. Army officer who killed 13 people in a shooting spree at Fort Hood in 2009. Hasan, it turned out, had been in extensive email contact with Awlaki in the months before the shooting, but no evidence ever emerged that Awlaki knew about his deadly intentions. 
 
 Still, Awlaki was operationally involved in numerous other terrorist attacks, including several attempts on the U.S. homeland. As chief of external operations for AQAP, al Qaeda’s affiliate in Yemen, he personally supervised the 2009 Christmas Day bombing attempt by the so-called underwear bomber. Less than a year later, he masterminded the package bomb plot, in which AQAP managed to place improvised bombs on cargo planes headed to the United States. (They were intercepted as a result of a tip by Saudi intelligence.) 
 
 We know Awlaki influenced the Tsarnaevs at least indirectly, through one of AQAP’s main propaganda organs. According to law enforcement sources, Dzhokhar has admitted to the FBI that he and his brother learned how to the build pressure cooker bombs they allegedly used in Boston from the terror group’s English-language Internet magazine, Inspire. For much of its existence, Inspire was run by Samir Khan, an American propagandist for AQAP who was close to Awlaki and was ultimately killed in the same U.S. drone strike that killed the Yemeni-American cleric. 
 
 The truth is that investigators are far from figuring out what ultimately made the Tsarnaevs pivot from radical thought to violent action. “That’s the million dollar question,” one counterterrorism official says. Despite all of the attention being paid to Tamerlan’s 2011 visit to Russia, law enforcement officials still believe the brothers’ path to extremism began much earlier in the United States. For one thing, they point out, the Russian security service, the FSB, had what it considered to be strong evidence of Tamerlan’s radicalization in March 2011, 10 months before he left for Russia. That was when the FSB reached out to its FBI counterparts at the U.S. embassy in Moscow and requested that the Americans check out Tamerlan. The FBI searched various databases for leads connecting Tamerlan to terrorism, viewed publicly available websites and social media he frequented, and, eventually, interviewed him. But it came up with nothing “derogatory,” in the FBI’s parlance, and eventually dropped the inquiry. 
 
 One reason the FBI may not have probed more aggressively, according to a U.S. official who has been briefed on the case, is that the Russians never revealed the basis for their suspicions. U.S. investigators assume the FSB had intercepted worrisome things Tamerlan might have said over the phone or in emails to suspected radicals they had under surveillance in Russia. But the Russians would have been loath to disclose what they had picked up for fear of revealing their sources and methods to a foreign intelligence service. 
 
 Mutual distrust between spy agencies goes with the territory, but the relationship between the United States and Russia has been especially fraught when it comes to cooperating on law enforcement and intelligence matters. One source of the FBI’s distrust is the perception that the Russians have tried to get them to spy on the Russian exile community in the U.S. under the guise of legitimate law enforcement. The FSB would have been particularly interested in Tamerlan because of his Chechen heritage. The Russians have fought two vicious wars with the predominately Muslim Chechnya, which has sought to break away as a separate state. A U.S. official told The Daily Beast that the FSB placed as many as 100 requests with the FBI for investigations into Chechens living in the United States between 2010 and 2012. Few if any of them panned out.
– Law enforcement officials have confirmed that it was Russia that told the FBI to investigate the slain Boston bombing suspect Tamerlan Tsarnaev in 2011, the AP reports. The FBI interviewed Tsarnaev, following up on the tip that he was a "follower of radical Islam," but didn't deem him a security risk at the time, reports Reuters. The FBI had said only that a foreign government had provided the intel, but two law enforcement officials, speaking anonymously, later revealed the Russian FSB intelligence security service as the source. The Tsarnaev brothers are ethnic Chechens—though they never actually lived in Chechnya—and Tamerlan visited Russia for six months last year, reports CNN. After getting the tip, the FBI not only talked to Tamerlan but checked out his travel history and web postings. The agency says it "did not find any terrorism activity." His mother says her elder son had embraced Islam but not religious extremism, and she was aware of his contact with the FBI. "How could this happen?" she asked on CNN. "They were controlling every step of him. Now they are saying this is a terrorist act." (Tamerlan, 26, who was killed in a shootout with police, had an American wife and toddler.)