North Carolina Republican Party Chairman Robin Hayes has been indicted by a federal grand jury as part of an ongoing corruption probe that threatens to consume his party.

Hayes, a wealthy and powerful former congressman, has been at the center of GOP power in the state for three decades. He was the party’s nominee for governor in 1996, served as a congressman from 1999 through 2009, and was its party chairman from 2011 through 2013, as well as since 2016.

The indictment relates to major donations made by North Carolina businessman Greg Lindberg, who federal investigators have been probing for white collar business crimes and his political contributions. Lindberg, Hayes and two others are charged with conspiracy to commit honest services wire fraud, according to court documents. They were also indicted for bribery related to programs receiving federal funds and a bribery scheme involving independent expenditure accounts and improper campaign contributions.

Hayes is also charged with three counts of making false statements to the FBI, according to the documents.

The Justice Department alleges that Lindberg, Hayes and two accomplices sought to bribe North Carolina Insurance Commissioner Mike Causey, a Republican. Causey appears to be cooperating with law enforcement in the case, and was not charged. The four men allegedly offered and gave millions of dollars in campaign support through an independent expenditure effort, and asked for Causey to remove a senior deputy commissioner responsible for regulating Lindberg’s company in exchange for the contributions.

The alleged events took place from April 2017 through August 2018, with Causey going to the authorities in January 2018. That’s months before the separate and unrelated voting fraud case in the North Carolina’s 9th congressional district took place.

The case was filed on March 18 and unsealed Tuesday, the same day Lindberg, Hayes and their alleged co-conspirators first appeared in court.

“The indictment unsealed today outlines a brazen bribery scheme in which Greg Lindberg and his coconspirators allegedly offered hundreds of thousands of dollars in campaign contributions in exchange for official action that would benefit Lindberg’s business interests,” U.S. Assistant Attorney General Brian Benczkowski said in a Tuesday statement. “Bribery of public officials at any level of government undermines confidence in our political system. The Criminal Division will use all the tools at our disposal—including the assistance of law-abiding public officials—to relentlessly investigate and prosecute corruption wherever we find it.”

After Lindberg funneled $500,000 to the state GOP, some of it earmarked for Causey’s campaign, he pushed Causey to fire a regulator and replace him with one of Lindberg’s own staffers, offering $1 million in independent expenditure support of his campaign if Causey made the move — a number that grew to $1.5 million in outside support and another $500,000 to the state party.

According to the Justice Department, Hayes knew of and discussed the bribes with Causey — and that Lindberg directed Hayes to transfer the bribe to his campaign, using the state party as an illegal pass-through to circumvent campaign finance limits. Hayes even warned in a private call with Lindberg against moving the money over in one lump sum because of worries that “someone would start asking questions,” according to the charging documents.

Hayes denied to the FBI that Lindberg had directed him to pass the funds along, a campaign finance law violation.

Hayes, through his lawyer, denied any wrongdoing.

“Robin Hayes steadfastly denies the allegations made against him in this case. After a long and distinguished career in public service at the local, state, and federal levels, Robin volunteered his time helping to support the party and candidates for office in North Carolina. We look forward to a swift conclusion to this matter, and to clearing his name,” Hayes attorney Kearns Davis told TPM via email.

The North Carolina Republican Party’s counsel, Josh Howard, said in a statement Tuesday that the party has been cooperating with the investigation for months.

“Early this morning, the North Carolina Republican Party was made aware of several indictments surrounding the conduct of a major donor to both major political parties and two of his associates. The Party has been cooperating with the investigation for several months, including staff members providing statements and responding to various document requests,” Howard said. “The Party, which has its day to day operations managed by professional staff under the direction of the NCGOP Central Committee, remains fully operational and focused on its mission at hand.”

Hayes announced on Monday that he would be stepping down as party chairman as of June, claiming complications from a recent hip surgery had convinced him to resign.

The North Carolina GOP has been in a huge amount of turmoil in recent months after it was revealed that a local GOP operative committed voter fraud to help House nominee Mark Harris win a close election last fall. That race’s results were thrown out after Harris’ own son testified in court that he’d warned his father against hiring the operative.

Hayes was close to Harris — both come from the religious conservative wing of the party. This investigation appears to be unrelated to that earlier scandal, however.

A North Carolina GOP spokesman declined to comment on the news, and its executive director didn’t respond to a request for comment for this story.

Read the indictment and Justice Department statement below:

This story was last updated at 1:15 p.m.