He tried "to minimize the extent and importance of his communications" and lied about when they started - after he joined the Trump campaign as a foreign policy adviser.
"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 well after the defendant's FBI interview as the government continued its investigation", the filing says. "The government understands that the Professor left the United States on February 11, 2017 and he has not returned to the United States since then", the sentencing memorandum stated, according to Bloomberg News.
But according to Mueller in the court document, when the Federal Bureau of Investigation sat Papadopoulos down for a two-hour interrogation on January 27, 2017, the former Trump adviser "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", according to a report by Politico.
Prosecutors working for special counsel Robert Mueller are recommending a short prison sentence for a former Trump campaign adviser who lied to the Federal Bureau of Investigation during the Russian Federation probe.
"The defendant lied in order to hide his contacts with Russians and Russian intermediaries during the campaign", the filing said.
It happened early in the investigation "when key investigative decisions, including who to interview and when, were being made".
One of the big mysteries is who in the Trump campaign Papadopoulos may have told about the Russians allegedly possessing Clinton-related emails.
In June, the Daily Caller News Foundation reported that Simona Papadopoulos said, "It looks to be one among a series of attempts to entrap George", adding, "The question today to me [is whether] these people are simply shady businessmen or are they part of a greater attempt to entrap George in illegal activity".
To make matters worse for Papadopoulos, the prosecutors say he has not provided significant help in their investigation.
Papadopoulos met with prosecutors four times to offer information after his initial interview and before he was charged with lying, the filing says.
An additional meeting in December where investigators wanted to ask Papadopoulos more questions - two months after he cut his plea deal - was canceled because he and his then-fiancée began giving interviews to media outlets. Mueller's filing suggests that Papadopoulos could get less than six months.
Mueller has also recommended a $9,500 fine.
Mueller's memo recommended that Papadopoulos be imprisoned for up to six months; a judge is expected to issue a ruling on his sentence in early September. In April, a judge sentenced him to 30 days in prison.