The FBI is investigating Texas Attorney General Ken Paxton, the Associated Press reported Tuesday evening, vetting allegations made by eight of Paxton's former top aides that he illegally used the power of his office to benefit a political donor.

Two unnamed sources told the AP that the bureau was examining claims made by the whistleblowers that Paxton broke the law by intervening several times in legal matters involving Nate Paul, a real estate investor and friend who donated $25,000 to Paxton's campaign in 2018.

On Sept. 30 and Oct. 1, eight aides in total told authorities that they believed Paxton had committed crimes as part of his relationship with Paul, citing bribery and abuse of office. Since then, four aides have been fired, three have resigned, and one has been placed on leave — sparking a whistleblower lawsuit.

Paxton, a Republican in his second term, has denied wrongdoing and said he will not resign his post, even as some in his own party call on him to do so and the state's top leaders call the allegations "concerning."

Earlier Tuesday, before the FBI investigation was made public, Paxton said in a statement that he knows "a little something about being falsely accused" and dismissed the allegations made by the whistleblowers as "overblown, based upon assumptions, and to a large degree misrepresent the facts."

Paxton has been under indictment for more than five years on securities fraud charges but has yet to stand trial. He has dismissed the charges as politically motivated and entered a not guilty plea.

Neither a campaign spokesperson for Paxton nor a defense attorney who is working on his long-running securities fraud case returned a request for comment about the FBI probe Tuesday. A spokesperson for the FBI declined to comment.

The full scope of Paxton's relationship with Paul remains unclear, though Paul has characterized it as friendly. In a deposition earlier this month, Paul revealed that he had employed a woman at Paxton's recommendation, though he said it was not a favor to Paxton. The woman had been involved in an extramarital affair with Paxton, according to two people who said the attorney general told them of the relationship in 2018.

Since the allegations surfaced last month, four examples have emerged of Paxton using his 4,000-employee agency to benefit Paul.

The whistleblowers allege Paxton tried to help Paul on a pair of open-records disputes, urging state employees to release documents that should have been confidential, and that Paxton rushed a legal opinion on foreclosure sales during the coronavirus pandemic, which helped Paul avoid such sales on several of his properties.

The attorney general's office — at Paxton's direction, the whistleblowers say — also took the highly unusual step of intervening in a lawsuit between Paul and an Austin-area charity.

And in September, Paxton hired an outside attorney to evaluate a complaint by Paul that he had been mistreated during an FBI raid on his property in 2019. Paxton's staff, the whistleblowers say, had already vetted the allegations and found them meritless, but Paxton continued to push the investigation.