The Washington Post reported on Wednesday that the woman, whom it didn't identify, played for the newspaper a recording of a telephone conversation she had with Barton in 2015. The Post said the recording captures the Texas Republican warning her against using the materials in a way that would hurt his political career. The woman detailed encounters and contacts she had with Barton over a five-year period beginning in 2011.
In a statement to The Post, Barton said a transcript of the recording provided by the newspaper may be "evidence" of a "potential crime" against him. He said he has been informed that the Capitol Police have begun an inquiry.
Capitol Police did not immediately respond to a request for comment from The Associated Press late Wednesday.
U.S. Rep. Joe Barton of Texas is apologizing after a nude photo of him circulated on social media.
Barton released a statement Wednesday saying that while separated from his second wife, prior to their divorce, he had sexual relationships "with other mature adult women."
The 68-year-old Republican from Ennis says each relationship was consensual and has since ended. He says, "I am sorry I did not use better judgment during those days. I am sorry that I let my constituents down."
Barton announced his re-election bid this month. The photo appeared on an anonymous Twitter account.
His spokeswoman told The Dallas Morning News that Barton has no plans to step down.
Barton joined the U.S. House in 1985. He's the longest-serving member of Congress from Texas.