Chambliss, of Georgia, says the U.S. was contacted once in March 2011 and again in November of that year. Another U.S. official says Russia provided the same information in both communications. The official spoke on condition of anonymity because the official was not allowed to speak publicly about the investigation.

Tsarnaev died in a police shootout.

The FBI has said Russia contacted the bureau once with concerns about Tsarnaev. The FBI said it told Russia that investigators found nothing to suggest he was part of an extremist group. It was unclear which part of the U.S. government received a subsequent request.