WASHINGTON — Despite being told in 2011 that an F.B.I. review had found that a man who went on to become one of the suspects in the Boston Marathon bombings had no ties to extremists, the Russian government asked the Central Intelligence Agency six months later for whatever information it had on him, American officials said Wednesday.

After its review, the C.I.A. also told the Russian intelligence service that it had no suspicious information on the man, Tamerlan Tsarnaev, who was killed in a shootout with the police early last Friday. It is not clear what prompted the Russians to make the request of the C.I.A.

The upshot of the American inquiries into Mr. Tsarnaev’s background was that even though he was found to have no connections to extremist groups, his name was entered into two different United States government watch lists in late 2011 that were designed to alert the authorities if he traveled overseas.

The picture emerging Wednesday was of a counterterrorism bureaucracy that had at least four contacts with Russian spy services about Mr. Tsarnaev in the year before he took a six-month trip to Russia in 2012, but never found reason to investigate him further after he returned, or at any time before last week’s attacks in Boston that killed 3 people and injured more than 260.