Yahoo had previously said about 32 million accounts had fallen victim to the deeper attack, which it said leveraged forged browser cookies to access accounts without the need for a password.
According to the indictment, FSB officers Sushchin and Dokuchaev also directed Baratov to use the information gained in the Yahoo breach to hack specific targets who possessed email accounts with other service providers, including Google.
When Baratov was successful, Dokuchaev would reward him with a bounty, the indictment charged.
Examples where Google accounts were targeted include an assistant to the deputy chairman of the Russian Federation, an officer of the Russian Ministry of Internal Affairs, and a physical training expert employed by the Russian government.
Details in the indictment reflect the often murky relationship in Russia between criminal hackers and government intelligence officers.
Interpol issued a “red notice” on Belan in relation to an earlier hacking campaign, according to the indictment. Instead of arresting Belan, however, the FSB recruited him to help with cyber espionage and provided tools to evade detection from other authorities.