Hardin also said that Watson spoke to the FBI about allegations of extortion regarding one of the 23 lawsuits filed against the quarterback, of which 22 are still active.
"In April, the FBI came to us and told us they were investigating a matter as to whether one of Mr. [Tony] Buzbee's clients had committed extortion in the way they were demanding money from Deshaun or what they would do if they didn't pay it," Hardin said in a news conference.
"We were not the ones who contacted them; they contacted us. We talked to [the FBI]. We even let them interview Deshaun -- and if y'all can find a lawyer that will let his client talk to the FBI if the lawyer had thought his client had done anything wrong or had any exposure, then I'll be very, very surprised."
On Friday, Buzbee, who represents the women suing Watson, told the League of Justice website that the FBI met with him to discuss Watson and spoke with several plaintiffs.
"I don't think they're investigating Deshaun," Hardin said. "What they're investigating is the allegations Buzbee has made in his lawsuits. I didn't know about that until yesterday, and then I checked it out and it's true. They are."
Hardin reiterated that Watson will "continue to cooperate" with all parties involved in the investigation.
"We will continue to cooperate with [the FBI] in any way that they want," Hardin said. "We have from the first cooperated with the Houston Police Department, cooperated with the district attorney's office, and we'll cooperate with the FBI, and ultimately, down the line, we'll cooperate with the NFL because we know Deshaun has done absolutely nothing wrong."
At his news conference, Hardin read what he said were text messages to Watson from the woman he is accusing of extortion. Hardin said the text messages do not mention an alleged attack on Dec. 28, 2020, during a massage session and that the woman said she "apologize[d] for my actions."
Buzbee told The Associated Press later Wednesday that Hardin is attacking the women who have sued Watson, saying Hardin is "focused on trying to attack me or my clients, and I'm tired of it."
Last month, Hardin told ESPN's John Barr that 10 women have filed complaints about Watson with the Houston Police Department. Eight of the women, according to Hardin, are among the 22 plaintiffs who have filed lawsuits against Watson.
Hardin said Watson has not spoken to the NFL as part of its investigation into the lawsuits.
"The NFL regularly tries to not reach out to the defendant and his lawyers and seek evidence from them until the criminal investigation is over," Hardin said. "Historically, they want to make sure they don't interfere with the criminal investigation. I have had no contact with the NFL except to call initially and say, whenever the time is appropriate, we will fully cooperate."
Information from The Associated Press was used in this report.