Here's who Mueller has charged in Russia investigation so far

Michael Flynn, President Trump’s former national security adviser, pleaded guilty on Friday to lying to the FBI regarding his contact with a Russian ambassador.

Flynn is the fourth person to be charged in Special Counsel Robert Mueller’s ongoing probe into alleged Russian interference in the 2016 election.

Here’s who has been charged so far:

Michael Flynn

FILE - In this Feb. 1, 2017 file photo, then-National Security Adviser Michael Flynn speaks during the daily news briefing at the White House, in Washington. The White House is refusing to provide lawmakers with information and documents related to President Donald Trump's first national security adviser's security clearance and payments from organizations tied to the Russian and Turkish governments. (AP Photo/Carolyn Kaster)

Michael Flynn plead guilty to lying to the FBI regarding his contact with a Russian ambassador.  (The Associated Press)

He was only Trump’s national security adviser for less than a month, but Michael Flynn still bedevils the administration. Flynn was charged and pleaded guilty to making false statements to the FBI.

Court documents show Flynn has told investigators a “very senior member” of the Trump transition team directed him to contact foreign governments, including Russia, over a United Nations vote – discussions tied to one of Flynn's false statements.

Paul Manafort

FILE - In this July 17, 2016 file photo, then-Trump Campaign Chairman Paul Manafort talks to reporters on the floor of the Republican National Convention at Quicken Loans Arena in Cleveland as Rick Gates listens at back left. Senate Judiciary Committee Chairman Chuck Grassley is considering issuing subpoenas to Manfort and two FBI officials close to fired director James Comey as part of the panel's investigation into Russian meddling in the 2016 elections.(AP Photo/Matt Rourke, File)

Paul Manafort remains on house arrest after he turned himself into authorities in October.  (The Associated Press)

Along with his former business associate, Paul Manafort turned himself in to federal authorities in October and remains under house arrest. Manafort, 68, served as Trump’s campaign manager for a few months in 2016.

The charges against him include: conspiracy against the U.S., conspiracy to launder money, unregistered agent of a foreign principal, false and misleading [Foreign Agents Registration Act] statements and seven counts of failure to file reports of foreign bank and financial accounts, a spokesperson for the Special Counsel's Office told Fox News.

The charges are related to consulting work Manafort and his colleague did for Ukraine. Manafort pleaded not guilty to the charges.

Richard Gates

FILE - In this July 21, 2016 file photo, Rick Gates, campaign aide to Republican presidential candidate Donald Trump, at the Republican National Convention in Cleveland.  Trump's former campaign chairman, Paul Manafort, and a former business associate, Rick Gates, have been told to surrender to federal authorities Monday, according to reports and a person familiar with the matter.(AP Photo/Evan Vucci, File)

Richard Gates pleaded not guilty to all charges.  (The Associated Press)

Richard Gates was charged at the same time as Paul Manafort. He is considered to be a protégé of Manafort and worked for Trump’s campaign as well.

Gates pleaded not guilty to all charges. 

George Papadopoulos

George Papadopolous_inline

George Papadopolous pleaded guilty in October to making false comments to the FBI.  (Fox News)

A former foreign policy adviser to Trump’s campaign, George Papadopoulos, pleaded guilty in October to making false statements to the FBI.

Papadopoulos was charged with willfully and knowingly making false statements to FBI agents regarding “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,” according to court documents.

Trump said “few people” knew of Papadopoulos on the campaign.

Kaitlyn Schallhorn is a Reporter for Fox News. Follow her on Twitter @K_Schallhorn.