Mifsud was not named in the court filing Friday night, but CNN learned the name of the mysterious "Professor" after Papadopoulos' guilty plea became public past year.
Get breaking news on your Mobile as-it-happens. Under federal guidelines, his recommended sentence is zero to six months, but prosecutors note another defendant in the case spent 30 days in jail for lying to the FBI.
Mueller said in the filing that Papadopoulos lied about his interactions with a suspected Russian agent, described in the filing as "the professor". "[But court documents] show Papadopoulos in touch with multiple "high-ranking" campaign officials once he was brought on board, and that he met with a professor with Russian ties who had promised to provide 'dirt" on Democratic nominee Hillary Clinton.
Prosecutors also detail a series of hard interviews with Papadopoulos after he was arrested in July 2017, saying he didn't provide "substantial assistance" to the investigation.
"The defendant's crime was serious and caused damage to the government's investigation into Russian interference in the 2016 presidential election", according to the memo signed by Mueller.
Papadopoulos was also the first Trump campaign adviser to plead guilty in Mueller's investigation. He denies any wrongdoing.More news: ICE Detained A Man Driving Pregnant Wife To Hospital
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The Maltese professor who gained global notoriety as the person who allegedly connected Trump's campaign with the Russians to destroy rival contestant Hillary Clinton may have escaped the United States and thus an FBI investigation due to lies told by Trump's ex aide.
"Instead of telling the truth, however, the defendant repeatedly lied throughout the interview in order to hide the timing and significance of information the defendant had received regarding the Russians possessing "dirt" on Hillary Clinton, as well as his own outreach to Russia on behalf of the campaign", Mueller said in the filing.
The court filing Friday states that Mueller's team is "aware that the defendant and his spouse have participated in several additional media interviews concerning his case".
In his guilty plea, Papadopoulos admitted that he had lied to Federal Bureau of Investigation agents during a February 2017 interview and misled them about interactions he had with Mifsud and his Russian contacts.
The filing suggests Papadopoulos hampered the FBI's ability to figure that out.
Van der Zwaan was sentenced in April. Papadopoulos said wrongly several times he had communicated with Mifsud before he joined the Trump campaign.
"The defendant lied in order to hide his contacts with Russians and Russian intermediaries during the campaign", the filing said.