RALEIGH, N.C. — The chairman of North Carolina's Republican Party and a secretive big-money donor are facing federal bribery and wire fraud charges accusing them of trying to sway regulatory decisions in favor of the donor's insurance companies, according to indictments unsealed Tuesday.

State GOP Chairman Robin Hayes and investment firm founder Greg Lindberg are among four people charged with bribery and conspiracy to commit honest services wire fraud. Hayes faces additional counts of making false statements. The four defendants appeared Tuesday before a federal magistrate.

Federal prosecutors said Hayes, Lindberg and two Lindberg associates promised or gave Republican Insurance Commissioner Mike Causey millions of campaign dollars to do things Lindberg wanted, such as seek the removal of a deputy insurance commissioner responsible for examining Lindberg's Durham-based insurance business. Prosecutors allege that the scheme ran from April 2017 through August 2018.

Prosecutors said in a news release that Causey, who wasn't charged in the indictment, voluntarily reported the scheme.

Lindberg's company, Global Bankers Insurance Group, is the parent or management company for a number of insurance businesses around the country. Lindberg also is the founder and chairman of the investment company Eli Global LLC.

"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," Assistant Attorney General Benczkowski said in a statement.

Hayes didn't respond to a message left on his cell phone, and a Lindberg spokesman didn't immediately respond to a phone message. A spokesman for the state GOP also didn't immediately respond to a message seeking comment.

Hayes, a 73-year-old former congressman, had announced Monday that he wouldn't seek re-election to his post with the state party. A news release from the party cited health reasons including a recent hip surgery as the reason for the decision.

Lindberg has given more than $5 million in political donations to North Carolina candidates, party committees and independent expenditure groups.