In a message posted to Telegram, a group calling itself Cyber Resistance said it had stolen correspondence from Lt. Col. Sergey Morgachev, who was charged in 2018 with helping organise the hack and leak of emails from the Democratic National Committee (DNC) and the Clinton campaign.

InformNapalm said in an article about the breach that it had confirmed Morgachev's identity by poring through personnel files and a curriculum vitae stolen by the hackers, including one document that identified him as a department head in Unit 26165 -- the same position which the FBI accused him of holding in 2018.

It is unclear what information the hackers had managed to steal or how significant it was. Morgachev's inbox could potentially hold insight into Russia's hacking operations, including the operation against Clinton and the Democrats.

The FBI described Morgachev as an officer in the Russia military spy agency, still known by its old acronym, GRU. It said his department was "dedicated to developing and managing malware," including the "X-Agent" spy software used to hack the DNC.

In its message announcing the theft, the group said of Morgachev: "A very cool and clever hacker, but ... We hacked him.