ESPN investigative reporter John Barr discusses the allegations levied against Dr. Larry Nassar, the longtime doctor for USA Gymnastics, and former coaches Bela and Marta Karolyi. (5:42)

A former member of the United States women's gymnastics team filed a civil lawsuit Thursday against Dr. Larry Nassar in California Superior Court, claiming the long-time team doctor for USA Gymnastics sexually assaulted her during medical exams and that the legendary former coaches, Bela and Marta Karolyi, failed to protect her and engaged in their own pattern of physical and emotional abuse. The suit also claims that top USA Gymnastics officials had "wide-ranging knowledge" of the abuse, but for years "concealed and ignored" it, enabling both Nassar and the Karolyis.

The claims against Nassar closely echo those made by a second former gymnast, a 2000 Olympic medalist, who sued Nassar and others in early September. Both suits claim Nassar sexually assaulted multiple team members, though the previous suit did not include specific claims against the Karolyis.

The woman who sued Thursday, now 24, was a member of the United States women's national team from 2004 to 2010, from ages 12-18, and is identified in the lawsuit under the alias "Jane Doe."

The defendants listed in the lawsuit, filed in California Superior Court in Los Angeles County, also include the Karolyis, USA Gymnastics, its current president Steve Penny, past president Robert Colarossi, and the gymnast's own private coaches, Galina Marinova and Artur Akopyan.

The sexual abuse is alleged to have occurred at the famed Karolyi Ranch in Huntsville, Texas, roughly an hour north of Houston. Since 2001, the ranch has served as the training facility for the U.S. women's national gymnastics team.

The lawsuit claims Nassar would interact with the teenager "under the guise of providing her care and treatments necessary for her to compete as a world-class, Olympic medal-winning gymnast." According to the suit, the doctor told her about "the need to do an 'intravaginal adjustment,' a fictitious guise where Nassar would digitally penetrate Plaintiff's vagina in order to adjust her bones. This 'intravaginal adjustment' was done without gloves, lubricant, and/or a chaperone, and was done for [Nassar's] own sexual gratification."

The lawsuit also alleges that Bela and Marta Karolyi "turned a blind-eye to Nassar's sexual abuse of children at the ranch" and "instituted a regime of intimidation and fear at the ranch for the minor children under their custody."

The lawsuit further accuses Bela and Marta Karolyi of:

Striking the gymnasts, scratching them until they bled and encouraging parents to hit their children.

Depriving gymnasts of food and water and searching the gymnasts' rooms to find and confiscate hidden food.

Screaming obscenities at the gymnasts; telling them that they were fat; and requiring them to strip to their underwear so that their physical appearance could be judged in front of their peers.

Reached on the phone Thursday at her ranch in Texas, Marta Karolyi told Outside the Lines, "If it's any legal matter, I have no comment on that." She declined to say anything further.

USA Gymnastics, when reached Thursday, provided the following statement:

"USA Gymnastics denies the allegations against it in this latest lawsuit. As we have made clear, when USA Gymnastics first learned of athlete concerns regarding Dr. Nassar, we dismissed him from further involvement and reported those concerns to the FBI. Still, the allegations that have been made are troubling. USA Gymnastics is committed to promoting a safe environment for our athletes. Due to the pending litigation and ongoing investigation, however, we are unable to comment further."

The other defendants, including Nassar, could not immediately be reached for comment.

The lawsuit says Nassar, as a doctor, and USA Gymnastics, as his employer, were obligated to report such abusive behavior.

"Bela and Marta Karolyi kept Nassar on because he was willing to keep their secrets, and when you have secrets in an environment with children, that's where pedophiles flourish." John Manly, attorney for the U.S. gymnast who is suing

"What we're really saying is the ranch was a toxic environment for these kids and a perfect environment for a pedophile to flourish," said John Manly, the attorney for both of the former U.S. gymnasts who have sued Nassar.

"[Bela and Marta Karolyi] had an obligation to make sure their environment was safe and they failed miserably. These were children and they were left alone with this man, who turned out to be a sexual predator," Manly added.

USA Gymnastics announced in July that it had purchased the ranch from the Karolyis, which since 2011 has been known as the USA Gymnastics National Team Training Center at the Karolyi Ranch. "Athletes of all ages and skill levels are impacted by the prestige and tradition embodied at the Ranch, and we are excited to continue the legacy of success," USA Gymnastics said in a press release announcing the purchase.

The lawsuit alleges the Karolyis allowed Nassar to "have unfettered and secluded access to minor children, including the Plaintiff, in the children's living and sleeping quarters," a violation of USA Gymnastics' own policies.

"Nassar would pre-sexually groom these minor children into believing that he was their friend and confidant," the lawsuit alleges, in contrast to "the oppressive and abusive treatment by [the Karolyis]," sneaking the gymnasts food, candy and other "contraband" to build trust.

"He built this relationship in order to sexually abuse these minors, including the Plaintiff," the lawsuit alleges.

The Karolyis enabled Nassar, according to the lawsuit, by engaging essentially in a quid pro quo: by turning a "blind eye to Nassar's sexual abuse of children at the ranch," the lawsuit claims, they ensured that he would never report their abuses.

"Bela and Marta Karolyi kept Nassar on because he was willing to keep their secrets, and when you have secrets in an environment with children, that's where pedophiles flourish," Manly said.

The lawsuit also alleges that Robert Colarossi, USA Gymnastics president from 1998 to 2005, and Steve Penny, the organization's president since 2005, "oversaw a wide-ranging, calculated concealment of numerous instances, complaints, and allegations of sexual abuse and misconduct."

Bela Karolyi, the former Romanian gymnastics coach, first gained fame for training 1976 gold medalist Nadia Comaneci. After defecting to the United States with his wife Marta in 1981, Karolyi went on to train a string of American Olympic gold medalists, beginning with Mary Lou Retton in 1984.

He was named U.S. National Team Coordinator in 1999, a position his wife, Marta, later assumed in 2001 until her retirement after the Rio Olympics. Marta was widely praised during the recent summer games for building the U.S. women into a powerhouse; the squad brought home nine medals from Rio, including the all-around team gold.

Nassar, 53, an osteopathic physician, worked with the U.S. women's gymnastics team from 1986 to 2015, first as a trainer and then, starting in 1996, as team doctor. He was a fixture at the Karolyis' ranch, where he treated dozens of elite-level gymnasts.

Nassar was fired by USA Gymnastics in the summer of 2015 after officials received complaints of sexual misconduct during medical exams.

"Immediately after learning of athlete concerns about Dr. Nassar in the summer of 2015, Steve Penny, president and CEO of USA Gymnastics, notified law enforcement," USA Gymnastics said in a statement released last month. "We also relieved Dr. Nassar of his duties, and he ceased to be affiliated with USA Gymnastics."

Penny would not comment to Outside the Lines, but a spokeswoman for USA Gymnastics acknowledged Penny reported the allegations against Nassar to the FBI.

Despite being released by USA Gymnastics, Nassar continued to practice medicine at his alma mater, Michigan State University, where he'd worked as a faculty member and treating clinician since August 1997. He also continued in his role as team physician for Twistars Gymnastic Club USA, in Michigan, and as a volunteer for the high school gymnastics squad in nearby Holt.

All of that changed in late August.

On Aug. 29, Rachael Denhollander filed a complaint with Michigan State University Police, claiming Nassar sexually abused her during a medical exam in 2000 when Denhollander was a 15-year-old club level gymnast. Denhollander, who initially told her story to the Indianapolis Star, declined to comment to Outside the Lines.

A day after receiving Denhollander's criminal complaint, Michigan State University suspended Nassar from treating patients at the school's sports medicine facility. He was fired by the school on Sept. 20. He is also no longer in his role with Holt High School. A Twistar employee told Outside the Lines that Nassar previously worked in a volunteer capacity for the club, but has not for months and is "not coming to the gym anymore."

Outside the Lines has learned that Denhollander's police report turned out to be the first of dozens filed with Michigan State University Police.

"We've received multiple additional complaints and we're continuing to receive more complaints," Michigan State University spokesman Jason Cody said.

Though Cody would not specify the number of complaints against Nassar -- or whether they were from gymnasts or other patients -- federal crime logs reviewed by Outside the Lines indicate that more than 30 complaints of criminal sexual conduct have been filed since the end of August in connection with addresses where Nassar treated patients not far from the Michigan State University main campus in East Lansing.

"I have approximately 20 other girls and women who've come forward to us that have alleged abuse by Dr. Nassar," Manly said.

Nassar has not been criminally charged.

He is being investigated in Michigan, though. Earlier this month the state's attorney general's office took over the increasingly sprawling case, citing its "complex" nature, which crosses into several different jurisdictions in Michigan and, possibly, other states.

"Nobody can put a time frame on when he might be charged," Nassar's attorney, Matt Newburg, told Outside the Lines, adding that there is no statute of limitations in Michigan for criminal sexual conduct in the first degree. Newburg and his co-counsel, Shannon Smith, declined to discuss the growing number of criminal and civil complaints against their client.

In the previous civil complaint, filed by a member of the 2000 women's gymnastics team, Nassar was accused of perpetrating similar assaults while the team was traveling for competition.

The former Olympian said in the suit that Nassar started "grooming" her when she first joined the team in 1994 and that he "would fondle and grope the [her] feet, ankles, thighs, buttocks, hips, waist, breasts ... and neck, placing [her] under the impression this inappropriate contact was part of treatment."

She also claimed Nassar openly discussed inappropriate topics during his treatments.

"[Nassar] would tell the minor Plaintiff that other gymnasts would give 'blowjobs' and described in detail the process of oral sex and other bizarre, explicit sexual innuendo," the lawsuit claims.

During the treatment, the September lawsuit claims, Nassar would "introduce his bare hand to Plaintiff's vagina and anus, on multiple locations, in Plaintiff's assigned sleeping quarters, as she lay on the edge of her bed, alone and without any supervision of a chaperone." Similar to the complaint filed Thursday, Nassar allegedly told the gymnast that he was performing a medical procedure called an "intravaginal adjustment."

The exams were conducted without gloves or lubricant and without a chaperone present, according to the lawsuit.

"Our belief is that he was performing a medical treatment that was taught, studied and commonplace," Newburg, Nassar's attorney, said when asked about the allegations in the September lawsuit. He spoke to Outside the Lines before Thursday's lawsuit was filed.

Doctors interviewed by Outside the Lines say intravaginal and intrarectal treatments have been used for decades to treat medical problems such as pelvic floor dysfunction, which can occur when muscles on the pelvic floor become weak or tight, and interstitial cystitis, a painful bladder syndrome.

"Under the right circumstances, this is an optimal type of therapy," said Kristene Whitmore, chairwoman and professor of urology, female pelvic medicine and reconstructive surgery at Philadelphia's Drexel University College of Medicine.

Whitmore said she has used the treatments herself on patients for nearly 30 years. While she never has had a gymnast come to her for treatment, Whitmore said "having an Olympic class gymnast who needs that type of treatment doesn't surprise me."

"But no gloves and examining a minor without a chaperone, that's just not what we do. It's supervised and our physical therapists have gloves on. Always," Whitmore said.

"People who have chronic pelvic pain can get help," Whitmore said "but it's also a matter of how you explain to the patient what the problem is and why you're about to do this type of treatment."

"I have tremendous respect and admiration for these brave women coming forward...It is essential that our athletes are safe and protected. If system changes need to be made for that to happen, then they can't come soon enough." Dominique Moceanu, 1996 U.S. Olympic team gold medalist

Nassar was first investigated for sexual misconduct in April 2014 at Michigan State University when a former student made "an allegation of abuse during a medical procedure," according to a statement released by the school. But it appears USA Gymnastics was not aware of that 2014 probe.

"Our police did an investigation. They then turned it over to the prosecutor's office and the prosecutor decided not to file charges," Cody, the MSU spokesperson, said.

Nassar was temporarily suspended from clinical duties at Michigan State during that 2014 investigation, but a spokeswoman for USA Gymnastics said the school never notified the sport's governing body.

"In 2014, Michigan State University investigated something and they didn't call us," said Leslie King, USA Gymnastics Vice President of Communications.

In a letter dated July 8, 2014, Nassar notified USA Gymnastics that he was resigning as National Medical Coordinator, but he continued to serve as team doctor for the women's artistic program until the summer of 2015.

The lawsuit filed in September by the former Olympian alleged USA Gymnastics "knew or should have known that [Nassar] had engaged in unlawful sexually-related conduct in the past." The more recent lawsuit made similar claims.

Just as Michigan State neglected to inform USA Gymnastics of its investigation of Nassar in 2014, the same was true in the summer of 2015, when members of the women's national team notified USA Gymnastics of possible sexual misconduct by Nassar.

USA Gymnastics never alerted Michigan State about the claims against Nassar, according to Cody, the MSU spokesperson.

"Either one of them could have picked up the phone. It's just a classic case of, 'We want to keep this quiet,' " Manly said.

"USA Gymnastics has cooperated fully with law enforcement since we first notified them of the matter, including -- at their request -- refraining from making further statements or taking any other action that might interfere with the agency's investigation," USA Gymnastics said in a Sept. 12 statement.

Though the allegations against Nassar were only recently made public, first through a series of articles published in the Indianapolis Star, allegations of abusive behavior by the Karolyis are not new.

In her 2012 memoir, Dominique Moceanu, who as a 14-year-old was part of the 1996 gold medal-winning U.S. Olympic team, alleged Marta Karolyi physically abused her, grabbing her by the neck and slamming her face into a phone, and that Bela Karolyi body-shamed her, criticizing her weight and forcing her to step on a scale in front of teammates.

"I have tremendous respect and admiration for these brave women coming forward to share their stories," Dominique Moceanu told Outside the Lines Thursday. "It is essential -- and a priority close to my heart -- that our athletes are safe and protected. If system changes need to be made for that to happen, then they can't come soon enough."

In 2008, former Romanian national team member Emilia Eberle told KCRA-TV in Sacramento that Bela Karolyi physically abused her, striking her on her head and body on multiple occasions while she trained for the 1976 Romanian Olympic team.

Gymnastics choreographer Geza Pozsar, who for nearly two decades was a fixture at the Karolyi Ranch, told Outside the Lines that he personally witnessed the abuse of Eberle, Moceanu and other gymnasts, who trained at the ranch.

"I have huge remorse that I was part of a system that was so brutal," Pozsar said.

Pozsar said he never saw Bela Karolyi strike female gymnasts in the United States, but he confirmed to Outside the Lines an account detailed in Moceanu's book, in which she writes that she was physically beaten by her father, a punishment for sneaking food into her dorm room, while Bela and Marta Karolyi stood idly by, watching.

Pozsar said he was not aware of any sexual abuse by Nassar at the Karolyi Ranch.

The former U.S. national team member who filed Thursday's lawsuit claims that she paid a steep price for the pursuit of her Olympic dreams. The lawsuit alleges that she has battled depression, panic attacks and eating disorders as a direct result of the abuse she suffered from Nassar and the Karolyis.

John Barr is a reporter for ESPN's Enterprise Unit. He can be reached at John.A.Barr@espn.com. Follow him @JohnBarrESPN. Enterprise Unit producer Caitlin Stanco contributed to this report.