DENVER -- Dr. Bill Moreau, who was dismissed in May 2019 as vice president of sports medicine by the United States Olympic & Paralympic Committee, filed a whistleblower retaliation lawsuit on Wednesday, claiming he was fired by the organization after he questioned the way top executives handled reports of sexual abuse and mental health concerns.

"Frankly, what I'm really worried about is, what if another kid gets raped and I didn't say something? What if another athlete kills himself and I didn't say something? Somebody has got to get the USOPC's attention to start listening and not breaking the law," Moreau told ESPN late Wednesday evening.

"We regret that Dr. Moreau and his attorney have misrepresented the causes of his separation from the USOPC," Luella Chavez D'Angelo, the Olympic committee's chief marketing and communications officer, said in the statement to the Denver Post on Wednesday. "We will honor their decision to see this matter through in the courts, and we won't comment on the specifics as that goes forward."

Moreau's lawsuit, filed in district court for the city and county of Denver, alleges that he was dismissed after 10 years at the USOPC (the organization changed its name in June 2019 to include Paralympic athletes) after repeatedly questioning the manner in which top executives handle reports of abuse and mental health concerns.

Among the allegations in Moreau's lawsuit:

• In the spring of 2018, at the Drake Relays in Des Moines, Iowa, Moreau said, a statutory rape occurred involving a 15-year-old female Paralympic athlete. The incident was mishandled by USOPC officials who failed to recognize a crime had even occurred when first reporting it to the U.S. Center for SafeSport. The offender in that case was later suspended by the center for "sexual misconduct involving a minor."

• In January 2019, Moreau said, the USOPC failed to dismiss a male strength and conditioning coach after he was spotted naked in a sauna by a female athletic trainer at the USOPC's Colorado Springs training center. The sauna was not in a locker room setting but rather was accessible to both male and female athletes, and the under-18 women's gymnastics team was training at the facility at the time of the incident.

• In February 2019, Moreau said, top USOPC executives failed to heed his warnings to provide psychiatric care to an Olympic cyclist, who at the time was suicidal. The athlete died by suicide a day after "Moreau's plea for urgent action," according to the lawsuit.

In a letter sent to her staff obtained by The Associated Press on Friday, USOPC CEO Sarah Hirshland defended the group's handling of the cases Moreau brought up in the lawsuit.

"It is important for you to know that we feel strongly that in the cases Bill Moreau uses as examples against us, we acted appropriately, expeditiously and in the best interest of the athletes," Hirshland wrote. "Unfortunately, he is mischaracterizing not only our actions -- but his own. We welcome the forthcoming process of providing perspective around those events."

A chiropractor by training, it was Moreau who once questioned the way disgraced former Team USA Dr. Larry Nassar treated athletes at the 2012 London Olympics. Moreau said he raised questions about Nassar's practice of treating members of the women's gymnastics program at their condominium in the athlete's village, rather than at the USOPC's central medical facility.

"In front of one of my colleagues, I told Larry Nassar to his face ... I told him it was safer for him ... I just said, you know, 'You need to treat in the big clinic where there's people around you ... and it's not good practice to treat people, juvenile females, in a one-on-one situation without a chaperone.'"

Moreau said Nassar explained that Marta Karolyi, the coordinator for the women's artistic program, wouldn't allow gymnasts to be treated in the USOPC's central medical clinic.

In follow-up visits, two of which were unscheduled, Moreau said he observed Nassar treating gymnasts in an open area, while Team USA athletic trainer Debbie Van Horn was also present.

"I thought, 'Well, you have a male, you have a female. It's in an open bay. Multiple athletes around here. I guess this is about as safe as it can get,'" Moreau said he concluded at the time.

What Moreau didn't know when he signed off on Nassar's treatment methods was that Nassar had sexually assaulted every member of the so-called "Fierce Five," the team that won gold in London.

Team USA gymnasts Aly Raisman, McKayla Maroney, Jordyn Wieber, Gabby Douglas and Kyla Ross have all since come forward publicly to identify as survivors of Nassar's sexual assaults.

Moreau said he was "crushed" by the revelations.

On May 13, 2019, Moreau said, he was informed he was being fired, effective immediately in a meeting with the USOPC's chief of sport performance, Rick Adams, and the organization's head of human resources. Adams cited a desire to hire someone with "a Doctor of Medicine (M.D.) degree rather than a Doctor of Chiropractic (D.C.) degree," according to the lawsuit.

Moreau contends that the dismissal was in direct response to a series of complaints he reported up the chain in 2018 and early 2019. The statutory rape involving the 15-year-old Paralympic athlete was among the first incidents, Moreau said, to create tension with his superiors.

Moreau said a track and field coach called him to report that the minor athlete was having suicidal thoughts after a 20-year-old male Paralympic athlete had sex with her in her room during the Drake Relays, where she was not accompanied by an adult chaperone. Moreau said he reported the incident to Adams and other USOPC executives.

At one point, Moreau said, the athlete's mother asked him, "Who the hell puts a 15-year-old girl in a room by herself?"

Moreau told ESPN he later received a report of the incident from USOPC's leadership. Next to a question that read, "Was a crime committed?" there was a box checked, "No," Moreau said.

"I couldn't believe it," Moreau told ESPN, adding, "They couldn't even recognize sex abuse when it was right in front of them."

Moreau said he pointed out to USOPC executives and Safe Sport investigators that a 15-year-old can't legally consent to sexual activity and that what happened at the Drake Relays constituted statutory rape and needed to be reported to law enforcement and child protective services.

In January 2019, Moreau said, he was equally dumbfounded when USOPC officials didn't immediately terminate a strength and conditioning coach who, at 10 a.m. on a Saturday, was spotted naked in a sauna by a female athletic trainer at a time when the under-18 women's gymnastics team was training at the USOPC facility. Moreau said a human resources investigator later explained to him that the coach was given an oral reprimand for his behavior.

"A gymnast could have walked right in there,'" Moreau said he told the human resources investigator, who responded that a reprimand was the "appropriate" response.

A month later, Moreau said, he became aware of an urgent mental health concern: An Olympic athlete had attempted suicide, and Moreau was informed the athlete had disengaged from follow-up psychiatric care.

While he said he was not involved in the athlete's care, Moreau said he learned that the USOPC planned to respond to the incident by forming a committee to meet and talk about how the organization might help the troubled athlete.

Sensing the situation required more immediate attention, on March 7, 2019, Moreau said, he met with Adams, the USOPC's chief of high performance.

"I said, 'Rick, this is serious, and if we don't change how we manage mental health, the next day, the next week, the next month, the next year, another athlete's gonna take their life ... And he just basically looked at me and was nonresponsive. That was on March 7. My birthday is on March 8, and that's the day she killed herself."

Moreau wouldn't name the athlete involved in the incident, but ESPN has learned that the athlete mentioned in Moreau's lawsuit was Olympian Kelly Catlin, a member of the USA Cycling national team. Catlin died by suicide at age 23 on March 8, according to family members. Catlin had won a silver medal in the 2016 Summer Olympics as part of the women's pursuit team and was a three-time world champion.

Moreau said the suicide by the former Olympian left him "despondent."

"I'm not saying we could have saved her, but we sure as hell could have tried," he told ESPN, adding, "I wasn't sleeping thinking about this person that I just feel was failed."

Moreau's lawsuit seeks unspecified damages.

Information from The Associated Press was used in this report.