Lev Parnas, a Soviet-born business associate with ties to Rudy Giuliani, President Donald Trump’s personal lawyer, raised the issue of executive privilege during a court proceeding Wednesday, arguing it could apply to some of the evidence gathered in his campaign-finance case in New York.

The issue was raised during an arraignment for Parnas and Igor Furman, who pleaded not guilty on Wednesday to charges in a four-count indictment that accused them of funneling money through straw donors into U.S. elections in an effort to gain influence. Prosecutors also allege the pair petitioned U.S. politicians, including a congressman, to have the ambassador to Ukraine removed from her post.

Assistant U.S. Attorney Rebekah Donaleski, offered a glimpse into the “voluminous” evidence that prosecutors have recovered so far on the two men who have become figures in the Trump impeachment proceedings, through “dozens of search warrants,” property searches, and subpoenas. The information includes emails and social media accounts and financial records from more than 50 bank accounts.

During the hearing, Parnas’ attorney, Edward MacMahon, told the judge that his client was told to invoke executive privilege in a letter that was submitted on Parnas’ behalf by John Dowd, a former lawyer for the president, to a congressional committee conducting the impeachment inquiry.

Asked by Judge Paul Oetken if Parnas has worked for the president, MacMahon said no, but that “he worked for Mr. Giuliani.” MacMahon said that his concern stems from Parnas having used Giuliani as his lawyer for both personal and business dealings and that Giuliani also works for Trump.

“There are issues that we need to be very sensitive to,” MacMahon said, not going into detail what those issues are. He continued, adding that he doesn’t “know who is looking at all this evidence. If information gets out that we determine it is all privileged, we’ve got a problem,” MacMahon said in court.

“I can’t invoke [executive privilege], only the President of the United States and the government can,” MacMahon said, telling the judge that he doesn’t know how to proceed if the issue arises. “I just wanted to raise the issue with you.”

Prosecutors, seemingly shocked by the executive privilege claim, told the judge that while “this is the first time that we’ve heard of this... we’re happy to have a conversation.” Donaleski, added that the government has already set up a “filter team,” a separate team of prosecutors within their investigation, who ensure that possibly sensitive information does not get exposed.

The judge instructed the two sides to discuss the issues over the coming weeks. Parnas and Fruman are scheduled to return to court on Dec. 2.

Flanked by his wife and attorneys, Parnas spoke briefly to the scrum of reporters outside the courthouse saying that he is looking forward to defending himself “vigorously in court.”

“Many false things have been said about me and my family in the press and media recently,” he said, before adding that he is “certain that in time the truth will be revealed, and I will be vindicated. In the end, I put my faith in God. Thank you.”

His defense attorney, Joseph Bondy, reiterated the sentiment, saying that his team “looks forward to defending Mr. Parnas in the court based upon the evidence and not a smear campaign that’s been driven by self-serving and misleading leaks apparently from the highest levels of our government.”

Prosecutors are also looking into Giuliani’s business dealings as part of their investigation, sources have told The Daily Beast and other news organizations.

Parnas and Fruman were arrested two weeks ago at Washington’s Dulles airport as they were preparing to board a flight to Frankfurt, Germany, holding one-way tickets. When prosecutors learned that the two were leaving the country, they moved quickly to secure the indictments, which were issued a day before the two were apprehended.

The two have both been released on $1 million bail and are relegated to house arrest while they await trial. Their movements have been restricted to New York, where the trial is scheduled to take place and the Miami area where they both live.

The case is the first criminal prosecution related to an apparent Trumpworld pressure campaign to coerce Ukrainian officials into digging up dirt on Trump’s political opponents for the 2020 re-election campaign, particularly former Vice President Joe Biden, an effort which is at the center of an impeachment inquiry underway by the U.S. House of Representatives.

Parnas and Fruman are charged in four-count indictment with making illegal straw donations, including a $325,000 contribution to the group America First Action, which was first reported by The Daily Beast.

That donation actually came from an entirely different, undisclosed company owned by Parnas. It is illegal to donate to federal political candidates in the name of another person or entity.

During an arraignment for David Correia and Andrey Kukushkin, two businessmen charged with conspiring with Parnas and Fruman to use straw donors to make illegal campaign contributions, prosecutors offered a broad brushstroke of “fairly voluminous” amounts of evidence they have gathered in the case from 10 search warrants and more than 50 bank accounts.

Parnas and Fruman are accused in the indictment in a separate scheme of helping Giuliani to dig up dirt on the president’s political opponents in Ukraine.

Prosecutors say that scheme involved having the former ambassador to Ukraine recalled. Giuliani believed the ambassador, Marie Yovanovitch, was standing in the way of investigations he and Trump wanted to see launched into Joe and Hunter Biden’s work in the country.

The campaign-finance allegations against Parnas and Fruman are inextricably linked with that effort. Prosecutors say their extensive political contributions, beginning in early 2018, were designed to curry favor with American policymakers in an effort to advance Parnas’ and Fruman’s political and business endeavors.