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. Of the four, Manafort has was the first to have been found guilty by a jury in part of Mueller’s probe.
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.
Here's a closer look at those who have faced charges throughout Mueller's probe.
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.
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.
On June 15, Manafort was jailed after a federal judge revoked his $10 million bail based on new witness tampering charges brought by Mueller.
Manafort was found guilty of eight financial crimes on Aug. 21 in the first trial victory of the special counsel investigation into the president's associates. He later pleaded guilty in a second case and agreed to cooperate with Mueller's team.
Richard 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 the former Trump campaign official is cooperating and providing useful 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.
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.
Papadopoulos was sentenced on Sept. 7 to 14 days in prison, 13 months supervised release, 200 hours community service and a $9,500 fine for lying to the FBI during the Russia probe.
“My entire life has been turned upside down, I hope to have a second chance to redeem myself,” he said during his sentencing.
Alex van der Zwaan
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, a law firm hired by the Ukraine Ministry of Justice in 2012 employed van der Zwaan. 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, a 28-year-old California man who sold bank accounts to Russians meddling in the election, pleaded guilty in February to using stolen identities to set up the accounts. He was sentenced in October to six months in prison, six months in home confinement and two years of supervised release.
The U.S. government said Pinedo did not know that he was dealing with Russians when he sold the accounts. Since his arrest, Pinedo has provided investigators with "significant assistance" in identity theft probes, prosecutors said.
During his sentencing, Pinedo told the judge he took "full responsibility" and understood "there needs to be consequences" for his actions. Federal sentencing guidelines called for Pinedo to serve between 12 and 18 months behind bars, but prosecutors did not recommend a particular sentence, noting his cooperation with officials.
While an unwitting pawn and small player in the Russia investigation, Pinedo's sentence is the most serious so far of any prosecution coming out of Mueller's work.
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.
Rosenstein announced the indictments, which stem from Mueller’s probe into Russia’s efforts to interfere in the 2016 presidential election.
Fox News' Samuel Chamberlain, Jake Gibson, Alex Pappas, Brooke Singman and The Associated Press contributed to this report.