JEFFERSON CITY – Attorneys for Missouri Gov. Eric Greitens are questioning why St. Louis Circuit Attorney Kim Gardner hired a private out-of-state company to perform the investigation that led to his indictment, rather than relying on St. Louis police.

Greitens' attorneys in a court filing Tuesday cited documents showing that Enterra LLC of Rochester Hills, Michigan, conducted the investigation connected to the Republican governor's affair with a woman in 2015, before he was elected.

A grand jury on Thursday indicted Greitens on one count of invasion of privacy for taking a partially nude photo of the woman without her consent and transmitting it to a computer.

Greitens is seeking a speedy trial and is eager to clear his name, attorney Edward L. Dowd Jr. said in a telephone interview Tuesday with The Associated Press. A judge on Monday set a tentative trial date of May 14. The Greitens team had hoped for an April trial date.

"The damage to this guy that's being done every day is absurd," Dowd said of Greitens, who along with his wife planned to unveil a portrait of George Washington Carver at the Governor's Mansion on Tuesday.

"He's hanging in there," Dowd said. "He's a very tough guy. He really wants to have a trial and so do we."

Dowd said he obtained the circuit attorney's contract with Enterra through an open-records request. That document, which Dowd filed as a court exhibit, shows Enterra was to be paid a $10,000 retainer, with its employees paid at a rate of $250 an hour plus reimbursement for "reasonable expenses."

The agreement states that the investigative company would report directly to Gardner "either orally, or if requested, in written form."

Dowd, a former U.S. attorney who also worked on the Branch Davidian investigation in Waco, Texas, said he's never seen a situation where a criminal case report was not in writing.

"It's more indication of how unusual this whole thing is," Dowd said.

It's unclear why an outside firm was used for the investigation instead of St. Louis police. A spokeswoman for Gardner had no immediate comment.

Washington University law professor Peter Joy said hiring a private firm to help in an investigation is not uncommon when prosecutors are understaffed and under tight deadlines. That was the case in the Greitens investigation because the three-year statute of limitations for invasion of privacy would have expired in March.

"When you are kind of under the gun, hiring outside help would be something you'd do," Joy said.

The court filing from Greitens' attorneys said the private firm is being paid at a rate eight times more per hour than city police earn, and questioned if the use of the outside firm instead of police will impact the admissibility of the evidence.

Gardner filed her own motion of discovery Tuesday noting that a photo of the woman is part of the evidence. It is not clear if the photo cited in the evidence listing is the one allegedly taken by Greitens.