The special counsel investigating Russian interference in the 2016 presidential election has told a judge that a former adviser to the Trump campaign repeatedly lied about his contacts with Russian operatives and “caused damage” to the government’s inquiry.
In a document filed Friday evening, the special counsel, Robert S. Mueller III, said that the former adviser, George Papadopoulos, misled investigators about the “timing, extent and nature” of the meetings. During one of them, Mr. Papadopoulos was told that Russia had damaging information about Hillary Clinton in the form of “thousands of emails.”
The memo said that Mr. Papadopoulos’s attempts to mislead the F.B.I. had a significant effect on the open investigation into whether President Trump or his advisers coordinated with Russia’s attempts to disrupt the 2016 presidential election.
“The defendant lied in order to conceal his contacts with Russians and Russian intermediaries during the campaign,” the memo said. It happened early in the investigation “when key investigative decisions, including who to interview and when, were being made.”
In particular, the document said that during a January 2017 interview with the F.B.I., Mr. Papadopoulos misled agents about his conversations with Joseph Mifsud, a London-based professor who investigators believe reached out to Mr. Papadopoulos on behalf of the Russian government.
“The defendant’s lies undermined investigators’ ability to challenge the professor or potentially detain or arrest him while he was still in the United States,” the memo said. “The government understands that the professor left the United States on Feb. 11, 2017, and he has not returned to the United States since then.”
Mr. Mueller’s memo recommended that Mr. Papadopoulos be imprisoned for up to six months; a judge is expected to issue a ruling on his sentence in early September. Thomas M. Breen and Robert W. Stanley, lawyers for Mr. Papadopoulos, said in a statement that they were not able to comment on the government’s sentencing submission at this time.”
During a meeting in spring 2016, shortly after he was named as an adviser to the Trump campaign, Mr. Papadopoulos was told by Professor Mifsud that the Russians had thousands of incriminating emails about Mrs. Clinton. It has long been a mystery whether Mr. Papadopoulos told anyone inside the Trump campaign about the Russian dirt, and the document filed Friday does not answer the question.
Mr. Papadopoulos did, however, make reference to the Russian dirt during a conversation he had in a London bar in May 2016 with the senior Australian diplomat in Britain. The Australians passed the information to the United States and, in July 2016, the F.B.I. opened its investigation into links between the Trump campaign and Russia.
Mr. Papadopoulos was arrested in July 2017 after he arrived in the United States from a vacation in Europe. He was questioned for several days and eventually pleaded guilty to lying to the F.B.I.
Mr. Mueller’s memo said Mr. Papadopoulos did not provide “substantial assistance” to the investigation, and that “much of the information provided by the defendant came only after the government confronted him with his own emails, text messages, internet search history and other information it had obtained via search warrants and subpoenas.”
Thirty-two people have been charged by Mr. Mueller’s office since it took over the investigation in May 2017. The only defendant to be sentenced so far is the lawyer Alex van der Zwaan, who pleaded guilty to making false statements about his conversations with a former Trump campaign official. In April, a judge sentenced him to 30 days in prison.
Mr. Mueller’s office has not yet filed a sentencing memo in the case of Mr. Trump’s former national security adviser, Michael T. Flynn. He pleaded guilty in December to making false statements to investigators about his contacts with the Russian ambassador and agreed to cooperate with the authorities.
Mr. Flynn was scheduled to be sentenced this year, but that has been delayed, suggesting that he is still cooperating with the government.