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AP Explains: The FBI is investigating Texas AG Ken Paxton

FILE - In this June 28, 2020, file photo, Texas Attorney General Ken Paxton waits on the flight line for the arrival of Vice President Mike Pence at Love Field in Dallas.  Paxton had an extramarital affair with a woman whom he later recommended for a job with the wealthy donor now at the center of criminal allegations against him, according to two people who said Paxton told them about the relationship. (AP Photo/Tony Gutierrez, File)
FILE - In this June 28, 2020, file photo, Texas Attorney General Ken Paxton waits on the flight line for the arrival of Vice President Mike Pence at Love Field in Dallas. Paxton had an extramarital affair with a woman whom he later recommended for a job with the wealthy donor now at the center of criminal allegations against him, according to two people who said Paxton told them about the relationship. (AP Photo/Tony Gutierrez, File) (Copyright 2020 The Associated Press. All rights reserved.)

DALLAS – The FBI recently opened a criminal investigation into claims that Texas Attorney General Ken Paxton abused his office to benefit a wealthy donor.

The probe, which was confirmed to The Associated Press by two people with knowledge of it who spoke on the condition of anonymity because the investigation is ongoing, marks an escalation in the latest controversy to surround the high-profile Republican, who has spent years under indictment on unrelated state securities fraud charges.

The FBI's interest in Texas' top law enforcement official arose from a rebellion by Paxton's top deputies, who accused him of breaking the law by using his office to help a wealthy donor with a troubled real estate empire who also hired a woman with whom the married Paxton allegedly had an affair.

Paxton has broadly denied wrongdoing and refused calls to resign, saying he'll seek a third term in 2022 and that he's prepared to fight it out in court. He has weathered other storms during his rise to becoming one of the country's leading legal crusaders for conservative causes.

With the complex drama likely to continue, here is what you need to know about Paxton's cases:

WHAT IS PAXTON'S BACKGROUND?

Paxton, a 57-year-old lawyer, was a Texas legislator before he became the state attorney general in 2015. His wife was later elected to his former state Senate seat representing Dallas suburbs.

An evangelical conservative, Paxton has positioned himself as a fierce fighter for right-wing causes and close ally of President Donald Trump. He has sued to overturn the Affordable Care Act, to end an Obama-era program that protected young immigrants from deportation, and to limit mail-in voting during the coronavirus pandemic.