Special Counsel Robert Mueller’s probe into alleged Russian interference in the 2016 election is ongoing.

So far, four Americans — Michael Flynn, Paul Manafort, Richard Gates and George Papadopoulos — have been charged, though none of the charges are directly related to misconduct by President Trump’s campaign. Additionally, more than a dozen Russian nationals have been indicted.

You can read more about their ties to the president, his campaign and the charges below. 

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

Paul Manafort turned himself in to federal authorities in October 2017. Manafort, 68, served as Trump’s campaign manager for a few months in 2016. Richard Gates, Manafort’s business associate, also turned himself in at the time. 

Manafort was indicted in connection with foreign lobbying work, and he pleaded not guilty. More specifically, the charges include: 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.

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.

Richard Gates

Like Manafort, Richard Gates was indicted in October in connection with foreign lobbying work and pleaded not guilty. His charges are the same as Manafort’s, ranging from conspiracy against the U.S. to conspiracy to launder money.  

Gates, who also worked for Trump’s campaign, pleaded not guilty to all charges. 

George Papadopoulos

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

Mueller’s team charged Alex Van Der Zwaan, an attorney who allegedly lied to federal investigators in the Russia probe, in federal court on Feb. 16.

According to charging documents, Van Der Zwaan was employed by a law firm hired by the Ukraine Ministry of Justice in 2012. He is accused of lying about his interactions with Richard Gates

13 Russian nationals

A grand jury indicted 13 Russian nationals and three Russian companies in February 2018 for allegedly interfering in the 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 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,” Deputy Attorney Gen. Rod Rosenstein, who oversees the special counsel probe, said.

Fox News’ Kaitlyn Schallhorn and The Associated Press contributed to this report.