Who's been charged by Mueller in the Russia probe so far?

Special Counsel Robert Mueller’s inquiry into alleged Russian interference in the 2016 election is ongoing – and secret.

So far, four former Trump campaign associates – Michael Flynn, Paul Manafort, Richard Gates and George Papadopoulos – have been charged, though none of the charges are directly related to any misconduct by the president's campaign.

Alex van der Zwaan, an attorney, pleaded guilty to lying to FBI investigators during the investigation, and was sentenced to 30 days in prison in April 2018. He was the first to be sentenced in the probe. 

The special counsel filed new tax evasion and bank fraud charges against Manafort and Gates in late February, potentially increasing the amount of prison time the pair could face if convicted at trial. The charges are similar to those filed in October.

Here's a closer look at those who have faced charges throughout Mueller's probe.

Michael Flynn

Michael Flynn, who served as Trump’s national security adviser for less than a month before resigning, was charged and pleaded guilty in December 2017 to making false statements to the FBI. 

Flynn reportedly lied about his talks with Russia's ambassador to Washington. In late 2016, while former President Barack Obama was still in office, the two allegedly spoke about the U.S. sanctions imposed on Russia.

This raised concerns that Flynn, a retired Army lieutenant general, misled Trump officials about his conversations with Russian officials.

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 turned himself in to authorities in October.  (The Associated Press)

The special counsel filed a 32-count indictment on Feb. 22 against former Trump campaign chairman Paul Manafort and aide Rick Gates, accusing the pair of tax evasion and bank fraud. 

The new indictment accused Manafort and Gates of doctoring documents to inflate the income of their businesses and then using those fraudulent documents to obtain loans. It also accused Manafort of evading taxes from 2010 through 2014 and, in some of the years, concealing his foreign bank accounts.

And on Feb. 23, a newly unsealed indictment accused Manafort of secretly paying former European politicians to lobby on behalf of Ukraine.

Manafort turned himself in to federal authorities in the fall. The 69-year-old served as Trump’s campaign manager for a few months in 2016. Gates, Manafort's business associate, also turned himself in at the time. 

Manafort was initially charged in a 12-count indictment in connection with foreign lobbying work, and he pleaded not guilty. The charges included: conspiracy against the U.S., conspiracy to launder money, false statements, unregistered agent of a foreign principal, and multiple counts of failure to file reports of foreign bank and financial accounts, according to a special counsel's office spokesman.

In June 2018, Mueller's team brought additional charges of obstruction of justice against Manafort and Konstantin Kilimnik, an associate.

Manafort sued to have the case against him dismissed and argued that Mueller had overstepped his bounds by charging him for conduct he says is unrelated to Russian interference in the 2016 election.

On June 15, however, Manafort was jailed after a federal judge revoked his $10 million bail based on new witness tampering charges brought by Mueller.

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)

Rick Gates was named alongside Manafort in the recent charges brought by the special counsel. He's accused of 11 counts related to filing false income tax returns and three counts of failure to report foreign bank and financial accounts.

Gates pleaded guilty on Feb. 23 to federal conspiracy and false-statements charges.

In wake of the guilty plea, Mueller moved to drop the 22 bank and tax fraud charges against him. The decision to drop the more expansive charges against Gates could suggest that the former Trump campaign official is cooperating and providing good information to Mueller's team.

Like Manafort, Gates was initially indicted in October in connection with foreign lobbying work; he pleaded not guilty at the time. His charges were similar to Manafort’s – ranging from conspiracy against the U.S. to conspiracy to launder money.

A superseding criminal complaint says Gates was charged with conspiracy against the United States between 2006 and 2017.

George Papadopoulos

george papadopoulos

George Papadopoulos pleaded guilty to the charges against him.  (Alexandria Sheriff's Office)

A former foreign policy adviser to Trump’s presidential campaign, George Papadopoulos pleaded guilty in 2017 to making false statements to the FBI 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.

He also reportedly tried to set up meetings between Russian and Trump campaign officials on various occasions. 

Alex van der Zwaan

Alex van der Zwaan arrives at a plea agreement hearing at the D.C. federal courthouse in Washington, U.S., February 20, 2018. REUTERS/Yuri Gripas - RC129AC156E0

Attorney Alex van der Zwaan pleaded guilty to lying to investigators about his interactions with Gates.  (Reuters/Yuri Gripas)

Mueller's team charged Dutch attorney Alex van der Zwaan for lying to federal investigators in the Russia probe in federal court on Feb. 16. He pleaded guilty and was sentenced to 30 days in prison and given a $20,000 fine on April 3.

Van der Zwaan was released from prison on June 4 and turned over to Immigration and Customs Enforcement officials. 

According to charging documents, van der Zwaan was employed by a law firm hired by the Ukraine Ministry of Justice in 2012. He admitted to lying about his interactions with Gates.

The charge against van der Zwaan did not involve election meddling or the Trump campaign's operations. It stemmed from the special counsel's investigation into a covert Washington lobbying campaign Manafort and Gates are accused of directing on behalf of pro-Russian Ukrainian interests.

The law firm where he used to work says it fired him last year and will continue cooperating with authorities as needed.

Richard Pinedo

Richard Pinedo, a California man who sold bank accounts to Russians meddling in the election, pleaded guilty to using stolen identities to set up the bank accounts in February.

The U.S. government said Pinedo did not know that he was dealing with Russians when he sold the accounts. The plea was announced on the same day that Mueller’s office charged 13 Russians and the indictment was the most direct allegation to date of illegal Russian meddling during the campaign.

Pinedo ran the online service Auction Essistance, buying and selling bank account numbers so customers could avoid security measures of digital payment companies, Newsweek reported. The Auction Essistance website says it is “currently undergoing scheduled maintenance.”

13 Russian nationals

A grand jury indicted 13 Russian nationals and three Russian companies in February for allegedly interfering in the 2016 election. In the case, Mueller details a sophisticated plot to wage “information warfare” on the U.S.

The indictment is the first to be brought against Russian nationals in Mueller's investigation. 

However, the Justice Department said the indictment does not allege that the interference changed the outcome of the election.

"There is no allegation in this indictment that any American was a knowing participant in this illegal activity," said Deputy Attorney General Rod Rosenstein, who oversees the special counsel probe.

12 Russian intelligence officers

The Justice Department on July 13 announced that 12 Russian intelligence officers were indicted for allegedly hacking the Democratic National Committee, the Democratic Congressional Campaign Committee and Hillary Clinton's campaign during the 2016 election.

All 12 are members of GRU, the Russian intelligence agency.

The indictments, which stem from the Special Counsel Robert Mueller’s probe into Russia’s efforts to interfere in the 2016 presidential election, were announced by Deputy Attorney General Rod Rosenstein.

Fox News' Samuel Chamberlain, Brooke Singman, Alex Pappas and The Associated Press contributed to this report. 

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