In December, in response to the American intelligence community’s conclusion
that Russia had tried to meddle in the presidential election, the Obama administration announced sanctions against Mr. Belan and Evgeniy M. Bogachev, who is also suspected of being a cyberthief and appears also to have ties to Russian intelligence.
The relationship between Mr. Belan and two Russian agents — Dmitry Aleksandrovich Dokuchaev
and Igor Anatolyevich Sushchin — was described in an indictment unsealed on Wednesday in federal court in San Francisco.
The indictment does not say how Mr. Belan was recruited, or whether the idea for the Yahoo breach originated with him or the F. S.B.
