Roh's name had come up in investigations by US Special Counsel Robert Mueller into alleged links between US President Donald Trump's 2016 electoral campaign and Russia or other foreign powers.
After being interrogated at the airport by the FBI and special investigators with the Mueller team, the 50-year-old lawyer says he and his family were “observed, followed and taped” by the FBI during their time in New York.
Officers with the bureau even booked rooms in the hotel where he was staying, the multimillionaire who commutes between homes in Zurich and Monaco, told Swiss daily Tages Anzeiger.
While a spokesperson for Robert Mueller refused to state whether Roh is currently under investigation, British broadcaster the BBC reported recently that Roh is suspected of having been the third member of a group that helped connect Trump's team with Russians.
The other members of this group are thought to include Maltese academic and self-styled diplomat Joseph Mifsud and Ivan Timofeev, the program director of the Valdai Discussion Club think tank which has close links to the Kremlin.
Roh's alleged role in establishing links between Russia and the Trump election campaign – something he strongly denies being part of – is difficult to ascertain.
In 2017, a former foreign policy adviser to the Trump campaign, George Papadopoulos, said under oath that he had met in March 2016 with Mifsud who Papadopoulos “understood to substantial connections to Russian government officials” according to court documents.
In April last year, both Mifsud and Roh both at a summit on energy politics held at the Valdai Discussion Club, where Timofeev was also present.
In the same month the academic, who has since vanished without a trace, told Papadopoulos he had “dirt” on Clinton in the form of “thousands of emails”.
Again, it is difficult to establish what, if any role Roh played. But in the United States, there is speculation that Roh could have been responsible for connecting the three other players in the drama.
Mifsud was a consultant at Roh's Zurich legal firm and previously formed part of the management at Italy's private Link Campus University which is partly owned by the lawyer's London-based UK company Drake Global.
Mifsud is also Roh's “partner and best friend” and “the money behind him”, Papadopoulos's wife Simona Mangiante, who also briefly worked for the Maltese citizen, told the Atlantic Monthly.
Meanwhile, Roh himself has strong Russian links. His Russian-born wife, a former student of Link Campus and the manager of the high-end Rohmir fashion label, is “extraordinarily well-connected” with clients including UK Prime Minister Theresa May according to the BBC.
But in a book set to be published next month titled “The Faking of Russia-Gate: The Papadopoulos Case” Roh argues strongly he had no role in the Trump campaign while he and his co-author Thierry Pastor claim Mifsud was not a Russian spy but “part of the game” with “close links to “Western secret services and the Clinton network.”
Arguing the alleged Russian connections to the 2016 US presidential election have been faked to discredit Trump, they also claim Papadopoulos was a Western intelligence operative embedded by the FBI within the Trump election team.