JEFFERSON CITY, Mo. — When Eric Greitens sought Missouri's highest office in 2016, his resume seemed hard to top: former Navy SEAL, former Rhodes scholar and founder of a veterans' charity. Most important, he said during the campaign, was his role as "a proud husband and father."

On Thursday, the square-jawed Republican governor fought allegations that he photographed his hairdresser naked while having an affair with her and threatened to publicize the image if she spoke about their relationship. The top prosecutor in St. Louis quickly launched an investigation. A bipartisan group of state lawmakers asked the attorney general to investigate as well.

Greitens acknowledged being "unfaithful" in his marriage but denied taking any naked photos and blackmailing the woman to stay quiet.

The governor and his wife released a statement late Wednesday after St. Louis television station KMOV aired a bombshell report that he had a sexual relationship with the hairdresser in 2015. The report included allegations from the woman's ex-husband, who secretly recorded a conversation with his ex-wife discussing the affair.

The affair was "a deeply personal mistake," the Greitens' statement said. "Eric took responsibility, and we dealt with this together honestly and privately."

Grietens, 43, has been seen as a rising star in GOP political circles. During the campaign, he cast himself as an outsider going up against a career politician, the state's Democratic attorney general. He barely hid his higher ambitions and reserved the web address ericgreitensforpresident.com years ago.

Through his attorney, the governor also denied an allegation from the ex-husband that Greitens slapped the woman, saying any accusation of violence is "completely false."

The woman involved did not comment on the record to the TV station, which did not name her. But her ex-husband, who also was not named, provided the audio recording to KMOV. On the recording, the woman gave details about a sexual encounter she says she had with Greitens in March 2015 at his St. Louis home. The woman did not know her then-husband was recording their conversation.

The Associated Press learned her identity Thursday, but chose not to identify the woman because she could not be reached for comment. She did not return a call to the salon where she works, and an AP reporter who went there was told the hairdresser was not working.

The alleged encounter came after Greitens created a committee to explore a bid for governor but before he officially announced his candidacy. She said on the tape that he invited her downstairs at his home because he wanted to show her "how to do a proper pull-up."

She said: "I knew he was being sexual, and I still let him. And he used some sort of tape, I don't know what it was, and taped my hands to these rings and then put a blindfold on me."

She said she later realized he took a photo of her.

"I saw a flash through the blindfold and he said, 'You're never going to mention my name.'"

A bipartisan group of state senators signed a letter asking the attorney general to investigate. Attorney General Josh Hawley's office said it would defer to local prosecutors, as required by state law.

The letter signed by both Democrats and Republicans called the allegations "deeply disturbing" and said a swift investigation was necessary to avoid having the matter "overpower" the 2018 legislative session.

GOP leaders in the Missouri Senate released a joint statement urging Greitens to be "honest and forthright." At least two Democratic state lawmakers called on the governor to resign.

The Legislature adjourned Thursday for the long Martin Luther King Jr. holiday weekend. Lawmakers were not scheduled to return until Tuesday.

Months after the affair, the hairdresser sent Greitens an email asking him to stop booking appointments at the salon.

The St. Louis Post-Dispatch reported that the email was sent Oct. 20, 2015, three weeks after Greitens filed papers formally starting his 2016 gubernatorial campaign. It was sent to the same account that Greitens listed on a website he used in the campaign.

The newspaper did not say how it obtained the email.

She asked Greitens, whom she called by his first name, to "please consider all who are involved and the circumstances around us." She said returning to the salon "isn't fair to me, nor anyone close to us" and that she needed to "move forward."

The lawyer for the ex-husband said the FBI has contacted him several times since October 2016 about the affair. Attorney Al Watkins said the agency has spoken to him about the affair and the blackmail allegations. He did not say if the ex-husband has also heard from the FBI.

A spokeswoman for the FBI's St. Louis office said the agency could not confirm or deny that it was investigating.

St. Louis Circuit Attorney Kim Gardner, a Democrat, initially said that no criminal complaint had been filed against Greitens and no evidence of a crime presented to her office. But after further consideration, she said, she concluded that an investigation is necessary.

Greitens' attorney, Jim Bennett, said the governor was "very confident he will be cleared in any investigation. This is a three-year-old personal matter that presents no matters of public or legal interest. The facts will prove that fully."

Bennett also alleged that reporting about the affair is being driven by former Missouri Democratic Party chairman Roy Temple and that it is clear "this is a political hit piece." Temple told The Associated Press that he met with the woman's ex-husband several times in September 2016. But when the man ultimately decided he didn't want to go public, Temple said he agreed not to publicize the affair. He said he has not spoken to the ex-husband since then.

Sheena Greitens is an assistant professor in the political science department at the University of Missouri and co-director of the university's Institute for Korean Studies. Much of her research focuses on China and North Korea.

The Greitens married in 2011 and have two young sons. The governor was married once before and divorced in 2003.

Watkins said his client and the woman who had the affair tried to reconcile but that the relationship with Greitens continued for several months and caused their breakup.

The ex-husband told KMOV that he believed the story would eventually be made public and he wanted to protect his family.