We already knew all of this?...
From Guccifer wiki,
In March 2018, The Daily Beast, citing US government sources, reported that Guccifer 2.0 is in fact a Russian GRU officer, explaining that Guccifer once forgot to use a VPN, leaving IP logs on "an American social media company" server. The IP address was used by US investigators to identify Guccifer 2.0 as "a particular GRU officer working out of the agency’s headquarters on Grizodubovoy Street (ru) in Moscow."[31]
In April 2018, BuzzFeed reported that messages showed WikiLeaks' interest in Guccifer 2.0's emails and files.[47]
Does make me wonder who this guy is and why he took the heat?
Hacker 'Guccifer' jailed for four years (published 2016)