US investigators have reportedly concluded that the Russia-linked hacker Guccifer 2.0 is directly tied to Russian military intelligence.

Security experts and the US intelligence community have long suspected the hacker's ties to Russian intelligence. But a new report Thursday said investigators recently obtained strong proof indicating Guccifer 2.0's ties to the Russian government.

The revelation directly contradicts President Donald Trump's claim that Russia was not working to tip the scales in his favor during the 2016 US election.

The Russia-linked hacker known as Guccifer 2.0 was long believed to be a front for Russian intelligence. On Thursday, The Daily Beast published a bombshell report confirming that the hacker has been directly tied to the GRU, Russia's military-intelligence outfit.

The US intelligence community concluded in January of last year, based on digital fingerprints left on hacks targeting Democrats during the 2016 presidential campaign, that the cyberattacks against the Democratic National Committee and members of Hillary Clinton's campaign were largely, if not entirely, carried out by Russian intelligence groups.

Guccifer 2.0, who has taken credit for some of the hacks, has denied ties to Russia, and security experts had reached a consensus that the self-proclaimed hacker was either a poser or the product of a Russian disinformation campaign. The cybersecurity firm ThreatConnect also determined that Guccifer 2.0 had been using a Virtual Private Network service, Elite VPN, to hide the origin of his or her efforts.

The Daily Beast reported Thursday that the hacker forgot to activate the service on one occasion, betraying the person's IP address and true location in social-media logs. US investigators have since used the information to identify Guccifer 2.0 as a specific officer at the GRU.

Guccifer 2.0's hack of the DNC and the subsequent dissemination of stolen materials wreaked havoc during the 2016 US election, and Clinton pointed to it as a major contributing factor to her loss to Republican Donald Trump.

The US intelligence community concluded last year that Russia mounted an elaborate, multifaceted campaign to interfere in the 2016 race that included hacking into and stealing information from DNC servers and an email account belonging to the Clinton campaign manager John Podesta. The intelligence community, as well as the special counsel Robert Mueller, determined that Russia carried out the effort specifically to cause chaos in US elections and boost Trump's candidacy.

Neither the intelligence community nor the special counsel have made a judgment on whether Russia's actions affected the outcome of the 2016 race.

Revelations about the true identity of Guccifer 2.0 will also most likely lead to heightened scrutiny of members of the Trump campaign who are known to have interacted with the person, like the longtime Trump confidant and informal adviser Roger Stone.

Stone told Business Insider last March that he had a private conversation on Twitter with the hacker and that the interaction was so "brief and banal, I had forgotten it."

"Not exactly 007 stuff even if Gruccifer 2.0 [sic] was working for the Russkies," Stone said. "Meaningless."

He also repeatedly cast doubt on the intelligence community's assessment that Guccifer 2.0 was a front for Russian intelligence, and he characterized the DNC hack as "an inside job."

Trump has denied that his campaign colluded with Russia to influence the election, and he has disputed the idea that Russia worked to tip the scales in his favor. But The Daily Beast's report tying Guccifer 2.0 to Russian military intelligence and the Russian government appears to be further proof of Russia's preference for Trump over Clinton.

Mueller has focused his scrutiny on the DNC hack over the past several weeks, and Thursday's report said he recently added the FBI agents responsible for tracking Guccifer 2.0's identity to his team.

The special counsel sent shockwaves through Washington when he indicted 13 Russian nationals and three Russian entities in February. His additional focus on the DNC hack and the actors behind it is yet another indication that his investigation isn't just limited to determining whether Americans were involved in Russian election meddling.