Nate Paul, a real estate investor and close associate of Texas Attorney General Ken Paxton, was arrested by the FBI Thursday afternoon, jail records show.

Paul was booked into the Travis County Jail in Austin, Texas, and is being held on a federal detainer for an undetermined felony charge, the records show.

When reached for comment, the FBI deferred to the US Attorney's office, which did not immediately respond to a request for comment. CNN has also reached out to Paul's attorney for comment.

The investor's relationship with Paxton is a key focus of impeachment articles brought against the embattled attorney general last month, CNN has reported.

The state House of Representatives voted to impeach Paxton after a legislative probe unraveled a yearslong pattern of corruption, including abusing his office's powers, retaliating against whistleblowers and obstructing justice.

The probe followed Paxton's effort to settle a lawsuit with four former employees of the attorney general's office after the whistleblowers accused Paxton of using his authority to benefit Paul, who had donated tens of thousands of dollars to the Republican's reelection campaign.

Several of the impeachment articles spotlight Paxton's relationship with Paul, including an accusation that Paxton used attorney general's office employees to write a legal opinion intended to help Paul avoid the foreclosure sale of properties owned by Paul and his businesses.

Both men have previously denied wrongdoing. CNN has reached out to Paxton for comment on Paul's arrest.

As Paxton awaits a state Senate impeachment trial, he is temporarily suspended from his duties.

Following the House vote to impeach the attorney general, Paxton called the move a "politically motivated sham."