Who is George Papadopoulos?

Papadopoulos pleaded guilty to making a false statement "about the timing, extent and nature of his relationships and interactions with certain foreign nationals whom he understood to have close connections with senior Russian government officials."

Thomas Breen, Papadopoulos' attorney, issued a statement declining to comment.

"We will have the opportunity to comment on George's involvement when called upon by the court at a later date," Breen said.

Here's the background on Papadopoulos:

Foreign policy adviser

Papadopoulos graduated from college in 2009, before moving to London to get a master's degree in security studies. He worked for the Hudson Institute from 2011 through 2015 in Washington, and was also briefly a foreign policy adviser to then-GOP presidential primary candidate Ben Carson -- now Trump's secretary of Housing and Urban Development -- before he joined the Trump campaign.

He is currently an oil, gas and policy consultant, according to his LinkedIn page.

Papadopoulos was living in London when he joined the Trump campaign as an adviser in March, according to a 14-page statement of offense signed by Mueller released Monday.

Papadopoulos' name first was raised in connection with the Trump campaign when Trump listed as one of his foreign policy advisers during a Washington Post editorial board interview.

A former Trump campaign official said Papadopoulos interacted with the campaign "a significant amount" during the 2016 election cycle.

"He was a foreign policy adviser," the official said. But the official described Papadopoulos as an adviser who was in contact with the campaign staff via email and not a familiar face around Trump Tower.

This official said Papadopoulos exchanged emails "constantly" on foreign policy matters with the Trump team during the campaign. Still, this official placed Papadopoulos in the same category as Carter Page who felt more like a "hanger-on" to the campaign staff.

In September 2016, the Russian Interfax News Agency interviewed Papadopoulos, where he said that the election of Trump would "restore the trust" between the US and Russia.

He also argued that US sanctions against Russia over the annexation of Crimea "have done little more than to turn Russia towards China as a primary market for Russian goods, services and energy."

Meeting with professor, Russian woman

The statement from Mueller says that Papadopoulos falsely claimed he met with an overseas professor before joining the Trump campaign in March 2016 about "the Russians possessing "dirt" on Hillary Clinton in the form of "thousands of emails."

At that point, however, he was already working for the Trump campaign -- the professor only took interest in Papadopoulos because of his status on the campaign, according to the statement. The professor told Papadopoulos about the Russians possessing dirt on Clinton in late April, and the statement says that "he repeatedly sought to use the professor's Russian connections to arrange a meeting between the campaign and Russian government officials."

Papadopoulos also met with a Russian woman in March 2016 along with the professor, according to the statement, and he relayed that information to the campaign.

During a March 31, 2016, foreign policy meeting with Trump and other campaign foreign policy advisers, Papadopoulos introduced himself to the group and stated "he had connections that could help arrange a meeting between then-candidate Trump and President Putin," according a factual statement signed by Papadopoulos in connection with his guilty plea.

Trying to set up a meeting

Papadopoulos continued to push a meeting with the Russians, and he sent multiple emails to other members of the campaign foreign policy team about his contact with "the Russians" and "outreach to Russia," according to the statement.

In April, the professor introduced Papadopoulos to a Russian national connected to the Russian ministry of foreign affairs, and they had conversations over Skype and email about setting up a meeting between Trump campaign and Russian government officials.

In late April, Papadopoulos learned about the "dirt" on Clinton, and the following day he emailed a senior campaign policy adviser: "Have some interesting messages coming in from Moscow about a trip when the time is right," according to the statement.

Papadopoulos continued to email high-ranking campaign officials about a request from Russia to meet Trump.

In May, Papadopoulos sent an email to a "high ranking Campaign official" with subject line "Request from Russia to meet Mr. Trump." The email said Russia was eager to meet with the candidate and have been reaching out.

In a footnote, the statement notes that the email was forwarded between campaign officials and who wrote they should discuss: "We need someone to communicate that DT is not doing these trips. It should be someone low level in the campaign so as not to send any signal."

The statement does not explain who the campaign officials were concerned about sending signals to.

The Washington Post reported in August that Manafort forwarded that email to his associate Rick Gates when he rejected the idea of Trump making a trip to Russia.

A separate foreign policy official for the campaign said Papadopoulos "obviously went to great lengths" to go around Trump's national security team, which was led by Sen. Jeff Sessions, now Trump's attorney general.