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A professor and author who once presented himself as a possible Trump administration ambassador to the European Union was detained and questioned by the FBI at Boston Logan airport and served a subpoena from Special Counsel Robert Mueller, who is probing possible collusion between Russia and the Trump campaign.

Ted Malloch said in an emailed statement to NBC News that he was flying from his home in the U.K. via Boston to Cleveland, Ohio to celebrate Easter when he was stopped Wednesday, an incident first reported by the Guardian.

NBC News has independently confirmed that Malloch was detained and questioned at the airport, but not the details of the encounter.

According to Malloch, when he exited his flight from London he was taken aside by a TSA official and an FBI agent, and separated from his wife. The TSA told NBC News that it had no involvement in Malloch's detention.

Malloch said two FBI agents then told him he was being detained to answer questions related to the special counsel's investigation.

He said they told him it was a felony to lie to the FBI and he told them he would "gladly" cooperate with them. According to Malloch, the agents also produced a document allowing them to seize and search his cellphone.

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At first, said Malloch, the agents questioned him about his career, showed him a color photograph of himself, and asked about his affection for the Philadelphia Eagles.

Then, said Malloch, "The questions got more detailed about my involvement in the Trump campaign (which was informal and unpaid); whom I communicated with; whom I knew and how well — they had a long list of names."

He said they asked him about former Trump campaign adviser Roger Stone, author Jerome Corsi and WikiLeaks. Malloch said he told them he met Stone a total of three times and always with groups of people, and that Corsi had helped edit one of his books years ago.

He said he was asked if he had ever visited the Ecuadorian embassy in London, where WikiLeaks founder Julian Assange has been living since 2012, and he replied no.

Malloch also said the agents served him a subpoena from Mueller's team that had been issued that day, March 28, and that he later arranged with the Special Counsel's Office to appear for questioning on April 13.

"What could they want from me — a policy wonk and philosophical defender of Trump?" said Malloch. "I am not an operative, have no Russia contacts, and—aside from appearing on air and in print often to defend and congratulate our President — have done nothing wrong. What message does this send?"

A spokesperson for the Special Counsel's Office would not comment on Malloch's statement or whether or not Malloch was questioned.

In November 2016, after Trump's upset victory in the presidential election, Malloch told the BBC he had been consulted by Trump throughout the campaign. He told reporters in early 2017 that he had interviewed for the position of U.S. ambassador to the EU twice. That position was vacated in January 2017 and is still vacant.

The Trump administration told reporters that Malloch had never been considered for the position.

Malloch has described the EU as having "evil" origins and compared it to the Soviet Union.

A former professor at the University of Reading in the U.K. and the author of several books, he has a book coming out in May called "The Plot to Destroy Trump: How the Deep State Fabricated the Russian Dossier to Subvert the President."

Roger Stone wrote the forward. Infowars host Alex Jones and Brexiteer Nigel Farage have written blurbs for the book cover, according to Malloch's publisher.