Prosecutors in Bulgaria have filed criminal charges against three Russian citizens in connection with the attempted poisoning in 2015 of arms dealer Emilian Gebrev.
Officials identified the suspects as Sergei Pavlov, Sergei Fedotov, and Georgy Gorshkov, saying that they are believed to be residents of Moscow.
In January, Bulgaria announced charges against three Russians in connection with the same case, but did not identify the suspects.
Earlier on February 21, the Bellingcat independent research organization posted on Twitter that it had "identified the true identities" of "the team of GRU officers" allegedly involved in the poisoning, using the abbreviation for the Russian military intelligence service.
"We have submitted relevant data to law enforcement," the Bellingcat post said.
In a further post, Bellingcat said it would make additional information public "next week."
In January, Bulgaria expelled two Russian diplomats believed to have been involved in the case.
Bulgarian authorities believe Gebrev, owner of the EMCO Ltd. arms trader; his son, Hristo Gebrev; and company manager Valentin Takhchiev were targeted in a poisoning attack "by intoxication with an unidentified phosphorus-organic substance."
All three survived the attacks.
In February 2019, Bellingcat identified Russian GRU officer Sergei Fedotov as possibly being involved in the March 2018 poisoning in the United Kingdom of former Russian intelligence officer Sergei Skripal and his daughter, Yulia.
Bellingcat alleged that Fedotov traveled to the United Kingdom two days before the attack on Skripal.
Russia has denied involvement in the attacks against Skripal and Gebrev.