Joseph Mifsud, the enigmatic Maltese academic at the centre of the criminal investigation into possible collusion between Russia and the Trump campaign, has disappeared.

US news network CNN reported that Mifsud has now “gone to ground,” after having been identified as a key figure in the FBI investigation into Russian influence over the 2016 US presidential election.

“Last Thursday, he disappeared from the private university in Rome where he teaches. Repeated attempts to reach him since have been unsuccessful, though he appears to have read some messages from CNN,” the report said.

Mifsud’s name emerged in the charges against President Donald Trump’s former aide, George Papadopoulos, who claimed that the Maltese academic and former diplomat told him in 2014 that the Russians were in possession of “compromising material” regarding presidential candidate Hillary Clinton.

Mifsud, who heads the international relations department at Rome’s Link University, rejected these claims insisting that while Papadopoulos is a friend of his, Trump’s former aide is “lying”. Papadopoulos was arrested in July. He admitted lying to FBI agents at the start of October, which is when he was offered a plea bargain in exchange for information on the email hacking scandal.

In a furtive interview with the Italian daily La Repubblica, Mifsud admitted going into hiding in his London office but dismissed reports of his involvement in the Clinton email scandal as “nonsense”.

In an interview with The Telegraph, Mifsud confirmed that he was the professor mentioned in the documents indicting Papadopoulos but rejected his portrayal in the latter’s testimony.

Papadopoulos told investigators that Mifsud had informed him that he had “substantial connections to Russian government officials” and promised “dirt” on Clinton in the form of “thousands of emails” obtained by the Russian government.

In an attempt to disassociate himself from the Trump campaign, Mifsud claimed he was a member of the Clinton Foundation, adding that he is a leftist who had, however, predicted Trump’s victory just as he had predicted Brexit.

“I don’t know anything. I absolutely exclude talking about secrets regarding Hillary. I swear on my daughter. I don’t know anyone at the Kremlin, the only Russian I know is Ivan Timofeev, the director of a Moscow based think-tank (the Russian International Affairs Council),” the London-based academic told La Repubblica.

When taken to task over Timofeev’s close links to the Kremlin, including having an office at the Russian Foreign Affairs Ministry, Mifsud said this was insignificant.

Despite denying ever meeting any Russian officials Joseph Mifsud (R), is seen, with Alexander Yakovenko, the Russian ambassador to the UK, in a photo from 2014

Despite previously telling the Daily Beast: “I do not know anybody from the Russian government…I am an academic,” Mifsud claimed that his meetings with Russian officials, including the Russian Foreign Minister Sergej Lavrov, were of a purely academic nature. He added “I am not a secret agent. I never got any money from the Russians: my conscience is clear”.

Mifsud is a regular fixture at the Valdai Discussion Club, a think tank based in the Russian city of Veliky Novgorod which has close links to Russian President Vladimir Putin. The think-tank hosts Mifsud every year for a keynote address.

Mifsud, who previously served as aide to Maltese Foreign Minister Michael Frendo, also claimed to be the director of the London Academy of Diplomacy, now affiliated with the University of Stirling in Scotland. However, the university identified Mifsud as a “full-time, professorial teaching fellow” in the politics department.