WASHINGTON U.S. authorities have long cast a wary eye on counterterrorism intelligence from Russia, Obama administration officials say, raising questions about whether a "trust deficit" clouded efforts to determine if Boston Marathon bombing suspect Tamerlan Tsarnaev posed a danger.
Any intelligence disconnect between the United States and Russia could have broader repercussions, complicating plans to cooperate on security for the 2014 Winter Olympics in the Black Sea resort of Sochi, not far from Russia's restive north Caucasus region.
U.S. officials said they consider counterterrorism information emanating from Moscow's bitter conflict with Islamist militants in Chechnya and other parts of the volatile north Caucasus especially suspect.
What little is known about how the FBI and other U.S. agencies handled a 2011 tip from Russia's FSB spy service that Tsarnaev, an ethnic Chechen, had become a follower of radical Islam suggests they dealt with it professionally, although not as a top-priority matter.
But it would not have been out of character for the U.S. government to take a jaundiced view of such information. In Tsarnaev's case, Moscow provided few details, U.S. officials have said.
"The Russians typically file spurious requests on people that are not really terrorists, and that's why somebody might have discounted it," a senior State Department official said. "One wouldn't automatically take what the Russians say at face value. You'd always have to look for a second corroboration."
Russian "watch lists" often include political dissidents and human rights activists mixed together with militants, the senior official said.
The Russian Embassy in Washington declined to comment for this story. But Russian President Vladimir Putin, who has repeatedly warned of the dangers of militancy from the Caucasus, may feel vindication by the Chechen connection to the Boston bombing.
Director of National Intelligence James Clapper touched on U.S. unease at Moscow's intelligence-sharing in a speech to a Washington conference on Thursday, in which he expressed pique at growing criticism over intelligence and law enforcement handling of the case.
"Whenever the Russians say something about arms control issues, well, we're very suspicious. We're supposed to trust but verify, not accept what the Russians say. But in this case, we accept it, whatever they say without question?" Clapper said with a shrug.
The FBI said it questioned Tsarnaev and found nothing to suggest he was a security threat. The bureau said it sought further details from the FSB, the post-Cold War successor to the KGB, but none were forthcoming.
Tamerlan, 26, was killed last week in a gun battle with police after the deadly April 15 Boston attack. His younger brother and alleged accomplice, Dzhokhar, 19, was later captured, wounded and hiding out in a suburban neighborhood.
CAN THEY PUT DISTRUST ASIDE?
More than two decades after the Soviet Union's collapse, the United States and Russia continue spying on each other. It was less than three years ago that they arranged a spy swap after the FBI arrested a cell of "sleeper agents."
Though Russia was quick to rally behind the United States after the September 11, 2001, attacks, tangible actions such as regular sharing of deep intelligence have proven harder.
The question now is whether the two countries can put distrust aside for the sake of better security.
One senior U.S. official insisted that both sides are committed, especially now that the Boston bombing has reminded everyone of the security risks ahead of the Sochi games.
"Our intelligence services are always conflicted between the need to share and the need to protect sources and methods," said the official, who spoke on condition of anonymity. "But we have a mutual interest as two countries that have been victims of terrorism ... . This will keep us focused."
In the lead-up to Sochi, Putin's pet project, the attack's Chechen link may give the Kremlin more leverage in its attempts to get the Americans to expand information on those whom Moscow brands "extremists" - even in cases where U.S. intelligence does not assess a real threat, the senior State Department official said.
The Obama administration is already debating whether to exchange terrorist "no-fly" lists as the Russians have requested and "act like everything they give us is legit," the official added.
Washington and Moscow have sometimes seen eye-to-eye on the Caucasus, In 2011, President Barack Obama and then-President Dmitry Medvedev agreed that the Caucasus Emirate militant group was a terrorist organization with al Qaeda ties. The United States offered a $5 million reward for the group's Chechen leader, Doku Umarov, the Kremlin's most-wanted man.
More recently, Putin has bristled at the Obama administration's criticism of what it sees as a heavy-handed response to a long-running Muslim insurgency in the Caucasus. Many analysts say the unrest has been fueled by Moscow's brutal repression.
A common view inside and outside of the Obama administration is that clashing assessments like these and disputes over intelligence clouded U.S. handling of the Tsarnaev tip.
"Over the last number of years - and it really goes back until at least 9/11 and probably before that - the Russians would come to us a lot and say, 'here's something bad that threatens you as well as us'," said Strobe Talbott, a Russia scholar and former deputy secretary of state.
"In many cases, the information was valid, and they were right. But sometimes there was a sense on the part of our professionals that they were exaggerating it ... and they were using it for political purposes," said Talbott, president of the Brookings Institution think tank in Washington.
Putin has long said the United States underestimated the security threat posed by an Islamist insurgency in the region, and has rejected criticism of Moscow's use of force. He cemented his rise to power by crushing an independence bid by Chechnya in the second of two wars there.
"The fact that a young Chechen might be angry is not in itself surprising," said Bruce Riedel, a veteran former CIA official and now a senior fellow at Brookings.
(Additional reporting by Mark Hosenball and Deborah Charles; Editing by Warren Strobel and Xavier Briand)