One of the key witnesses of former FBI director and attorney Robert Mueller during the investigation of alleged Russian collusion in the 2016 presidential election was accused of concealing the source of millions of illegal dollars that were donated to Hillary Clinton’s campaign.

Lebanese-born U.S. businessman George Nader was accused of conspiring with co-defendant Ahmad ‘Andy’ Khawaja of e-commerce company Allied Wallet for concealing the source of more than $3.5 million in illegal contributions to Clinton’s campaign, according to a statement issued by the Department of Justice.

According to the Washington Examiner, Nader and Khawaja received the indictment from the federal grand jury of the District of Columbia, which was responsible for specifying the 53 charges before revealing the indictment on Tuesday, Dec. 3.

Khawaja donated more than $4 million to Hillary Clinton’s and other Democrats’ campaign in the 2016 cycle, and later, once the race for president was over and Donald Trump became the new president, Nader donated $1 million to Trump’s inaugural committee, according to The Associated Press.

While no particular candidate is mentioned, Federal Election Commission reports, in addition to the details specified in the indictment, indicate that the money raised went to support Clinton’s campaign efforts in 2016.

“By design, these contributions appeared to be in the names of Khawaja, his wife, and his company. In reality, they allegedly were funded by Nader,” said Assistant Attorney General Brian Benczkowski of the Justice Department’s Criminal Division in the statement.

“Khawaja and Nader allegedly made these contributions in an effort to gain influence with high-level political figures, including the candidate. As Khawaja and Nader arranged these payments, Nader allegedly reported to an official from a foreign government about his efforts to gain influence,” the document adds.

Other charges in the indictment indicate that Khawaja, along with six associates (Roy Boulos, Rudy Dekermenjian, Mohammad Diab, Rani El-Saadi, Stevan Hill, and Thayne Whipple) were involved in a conspiracy to conceal executive contributions valued at more than 1.8 million, earmarked for different political committees from 2016 to 2018.

As the Washington Examiner has pointed out, Nader is in federal custody after being charged last July with sex trafficking for allegedly transporting a 14-year-old boy from Europe and then abusing him.

He then pleaded not guilty before a jury in federal court in Alexandria, Virginia.

Nader also pleaded guilty in 1991 to a federal child pornography charge involving photographs of 14- and 13-year-olds, leading to a six-month sentence he ended up serving in a Baltimore halfway house, according to News Punch.