FILE - In this Jan. 29, 2018, file photo, Missouri Gov. Eric Greitens speaks in Palmyra, Mo. A St. Louis grand jury has indicted Greitens on a felony invasion of privacy charge related to the Republican's affair with a woman in 2015. St. Louis Circuit Attorney Kim Gardner announced the indictment Thursday, Feb. 22, 2018. She launched an investigation in January after Greitens admitted to an affair with his St. Louis hairdresser that began in March 2015. He was elected governor in November 2016. (AP Photo/Jeff Roberson, File)
FILE - In this Jan. 29, 2018, file photo, Missouri Gov. Eric Greitens speaks in Palmyra, Mo. A St. Louis grand jury has indicted Greitens on a felony invasion of privacy charge related to the Republican's affair with a woman in 2015. St. Louis Circuit Attorney Kim Gardner announced the indictment Thursday, Feb. 22, 2018. She launched an investigation in January after Greitens admitted to an affair with his St. Louis hairdresser that began in March 2015. He was elected governor in November 2016. (AP Photo/Jeff Roberson, File)

St. Louis — A St. Louis grand jury on Thursday indicted Missouri Gov. Eric Greitens on a felony invasion of privacy charge for allegedly taking a compromising photo of a woman with whom he had an affair in 2015. The Republican governor responded that he made a mistake but committed no crime.

St. Louis Circuit Attorney Kim Gardner launched an investigation in January after Greitens admitted to an affair with his St. Louis hairdresser that began in March 2015.

He was elected governor in November 2016.

Thursday’s indictment was followed with an announcement by House Republican leaders that they were forming a group of lawmakers to investigate the charges “and answer the question as to whether or not the governor can lead our state while a felony case moves forward.”

In a statement following the indictment, the Republican governor was defiant and attacked the prosecutor who brought the charge.

“As I have said before, I made a personal mistake before I was governor,” he said. “I did not commit a crime. With today’s disappointing and misguided political decision, my confidence in our prosecutorial system is shaken, but not broken. I know this will be righted soon. The people of Missouri deserve better than a reckless liberal prosecutor who uses her office to score political points.”

Greitens’ attorney, in a separate statement, called the indictment “baseless and unfounded.”

“In 40 years of public and private practice, I have never seen anything like this,” attorney Edward L. Dowd Jr. said.

Greitens’ legal team immediately filed a motion to dismiss the indictment on the grounds that any relationship with the woman was consensual.

Gardner, a Democrat, declined comment beyond a brief news release.

Some lawmakers renewed suggestions that Greitens should consider resigning, as they had done when the affair first become public last month.