The Maltese professor suspected of being a link between Russia and the Donald Trump campaign made repeated visits to Russia in recent years, including participating in conferences at a Russian think tank favoured by President Vladimir Putin.
Joseph Mifsud has been identified as the unnamed London professor who offered to set up meetings with Russian officials who could provide "thousands of emails" with damaging information about Mr Trump's rival, presidential candidate Hillary Clinton.
He is a vocal Putin backer with ties to several important institutions in Russia.
Prof. Mifsud has visited Russia at least once a year since 2014, most recently in September, online postings on Russian academic sites show.
He has taken part in events at the Valdai Discussion Club favoured by the Russian leader and lectured at Moscow State University.
In the US court document laying out the case against former Trump foreign policy adviser George Papadopoulos, Prof. Mifsud is not identified by name and is referred to only as a "London professor".
He is said to have met repeatedly with Papadopoulos and offered to set up meetings with Russian officials who could provide dirt on Clinton.
However, a comparison of court papers and Papadopoulos' email correspondence obtained by The Associated Press confirm Prof. Mifsud is the professor.
Prof. Mifsud, who has not been accused of any wrongdoing, told The Telegraph newspaper he is the "London professor" in the case and says his conscience is clear.
READ: 'Nothing sinister' about Mifsud's Russian contacts, says former employer
Papadopoulos, 30, has pleaded guilty to lying to the FBI. He is not contesting the facts laid out in court documents, calling them "true and accurate", and is now cooperating with the FBI - and has been doing so for several months.
That raises the prospect that he has agreed to surreptitiously record conversations with people involved with the Russian government and the Trump campaign.
While Prof. Mifsud appears to have extensive ties to several important institutions in Russia, the Maltese native's academic credentials in Britain are far hazier.
He holds a professorial teaching position in the politics department at the University of Stirling in Scotland, according to officials there who said he took up the post in May.
However, he is not named on the university's list of experts and the university press office refused to say how often he is on campus, where a reporter on the student newspaper said he does not maintain an office.
We haven't been able to find a single student who has met with Professor Mifsud or attended any lectures by him at Stirling
"There is no evidence Prof. Mifsud has even been to the university since joining the staff in May," said Craig Munro, a reporter at the campus newspaper, Brignews.
"He doesn't have an office here and is based in London. We haven't been able to find a single student who has met with Professor Mifsud or attended any lectures by him at Stirling."
Prominent British academics also say they have had little or no contact with Mifsud.
"I've never heard of him," said Robin Niblett, the veteran director of Chatham House, the prominent London think tank.
Nor has Mr Niblett heard of the now-defunct London Academy of Diplomacy, where Prof. Mifsud is said to have served as "honorary director" before it closed according to his biography.
He has also not heard of the London Centre of International Law Practice, where Prof. Mifsud is listed as director of international strategic development.
"He seems to be a classic case of someone floating around on the fringes of the academic world and the think-tanky world without landing anywhere," Mr Niblett said.
"It would strike me that most of these positions are not paid, which raises questions. No doubt Russia cultivates certain academics. There's no reason to assume he was consciously part of a disinformation operation, but he may have been unwittingly used for that purpose."
According to the US court documents, Prof. Mifsud introduced Papadopoulos to a woman referred to as a "female Russian national" whom he falsely presented as a Mr Putin's niece and who he said could serve as a potential link to the Russian government.
There is evidence of Prof. Mifsud's ties to several key Russian institutions
He took part in events at the Putin-linked Valdai think tank in April 2016 that dealt with "What Russia Can Do to Bridge Saudi-Iranian Differences" and "Main Trends and Scenarios of Global Energy Development".
In 2012, Prof. Mifsud was instrumental in establishing a partnership between the now defunct London Academy of Diplomacy and the Faculty of Global Processes at the Moscow State University, according to the faculty's website.
On behalf of the academy, Mr Mifsud signed a wide-ranging cooperation agreement with the Moscow State University faculty in 2014 calling for shared research, student and teacher exchanges, the establishment of joint advanced degree programmes and a commitment to hold conferences together and publish joint research.
Prof. Mifsud has also lectured at the Moscow university and frequently moderated its panels.
A report on his 2014 visit on the faculty's website featured a picture of him trying on a T-shirt and a baseball cap with the faculty's symbols.
The next year, Prof. Mifsud joined dozens of people along with several Russian officials and prominent academics in signing a note congratulating the faculty on its 10th anniversary.
His most recent visit to Russia appears to have been in late September when he moderated panels at the faculty's two-day Global Studies Conference.
He is also credited with helping Moscow State University set up an educational center in conjunction with Link Campus University, a private university based in Italy.