(CNN) - One by one in court, Larry Nassar's victims spoke with the strength of survivors to shame the man who abused them and the adults who silenced them.
Some Olympic gymnasts as well as former and current athletes described how they moved quickly to report the ex-USA Gymnastics team doctor when he left them frightened and hurt beyond words.
But the adults they trusted failed to tell authorities or were slow to react to allegations. That inaction fostered the perfect environment for a serial sexual predator to run rampant, many victims recalled.
Nassar has pleaded guilty to seven counts of criminal sexual conduct in Ingham County, Michigan, and has admitted to sexually assaulting and abusing young girls under the guise of providing medical treatment. He's expected to be sentenced Tuesday and faces up 125 years in prison. He has already been sentenced in another court to 60 years in prison on child pornography charges.
Here are some of the people and organizations named by the victims in court and in several lawsuits. They have not been named as perpetrators, but as those who dismissed allegations about Nassar's misconduct throughout the years.
Former MSU gymnastics coach Kathie Klages
•The accusation: At 16, Larissa Boyce was training at the same gym as many of her role models when Kathie Klages -- a gymnastics legend in Michigan -- said she had potential.
"She was the person I looked up to. She was the person I thought had my back," Boyce said while reading her victim impact statement in court.
Twenty years ago, Boyce told Klages -- who was then the head coach of the gymnastics team at Michigan State University -- that Nassar had abused her.
Boyce is among the first athletes known to have complained to MSU staffers about Nassar. Nassar treated non-MSU students -- many of them children or teenagers -- on campus.
"Instead of being protected, I was humiliated. I was in trouble and brainwashed into believing that I was the problem," said Boyce, who at the time was a member of MSU's youth gymnastics program.
Boyce recalls Klages telling her that she could not imagine Nassar "doing anything questionable," then discouraging her from filing a formal complaint, according to a federal lawsuit.
"This could have stopped in 1997," Boyce said. "But instead of notifying authorities or even my parents, we were interrogated. We were led to believe we were misunderstanding a medical technique."
"I was not protected by the adults I trusted," she said.
• What is Klages saying now? Klages' attorney, Steve F. Stapleton, told CNN his firm is representing the former coach in the federal civil litigation surrounding Nassar and will not comment on pending litigation. Klages retired in 2017.
Michigan State University trainers and staffers
•The accusation: At least three MSU trainers listened to Tiffany Thomas-Lopez's horrific tale of abuse in the late 1990s and none of them did anything, she alleges in a lawsuit.
Thomas-Lopez was attending MSU on a scholarship when she went to see Nassar, hoping that he would treat her chronic back pain.
After Nassar touched her vagina during an office visit, she immediately reported the assault to her trainers but was told that Nassar "was a world renowned doctor" and that she had just experienced a "legitimate medical treatment," according to a federal lawsuit filed last year.
She went to see her trainers again after Nassar had her remove her pants to then put his ungloved hand in her vagina, the document states.
"The supervisor dismissed my complaints and basically treated me as though I were crazy," Thomas-Lopez told CNN affiliate KTLA. "She indicated that Dr. Nassar used this procedure with many female athletes."
"The army you chose in the late '90s to silence me, to dismiss me and my attempt at speaking the truth will not prevail over the army you created when violating us," Thomas-Lopez told Nassar in court last week.
•MSU's response to the accusation: Patrick Fitzgerald, the lead attorney for MSU in the civil cases, is defending the university's response to the scandal.
"The evidence will show that no MSU official believed that Nassar committed sexual abuse prior to newspaper reports in the summer of 2016," he wrote in a December letter to the Michigan attorney general.
The FBI and MSU Police Department conducted a joint investigation last year to "determine whether any university employee other than Nassar engaged in criminal conduct" and no criminal charges have been filed in connection with that investigation, the university said.
"We have no reason to believe that any criminal conduct was found," said Jason Cody, a MSU spokesman.
•The accusation: The governing body for gymnastics in the United States has been criticized for being slow to act when organization officials first received reports of Nassar's misconduct in 2015.
Nassar was the team physician for about two decades.
Star collegiate gymnast Maggie Nichols was the first one to accuse Nassar after a coach who overheard her talking with a teammate about the doctor took her to see USAG's officials, Nichols wrote in a statement.
But five weeks passed before the group called the FBI, according to a timeline of events released by the organization.
John Manly, an attorney who represents 107 victims in civil lawsuits, said USAG also failed to inform Michigan State University of those abuse allegations. The school employed Nassar for several months following Nichols' report before a criminal investigation against the doctor was launched.
Manly has said the organization also tried to keep the investigation secret ahead of the 2016 Olympics.
A lawsuit filed last month alleges that USAG paid Olympic gold-medal-winning gymnast McKayla Maroney to keep quiet about abuse by the team's longtime doctor.
The suit said Maroney "was forced to agree to a nondisparagement clause and confidentiality provision" in 2016 as part of the settlement that held "a six-figure liquidated damages clause over the head of McKayla Maroney and her parents."
•What is USAG saying? USAG interviewed a total of three athletes before contacting the FBI in July 2015. An independent investigator looking into Nassar's conduct initially talked to Nichols and another athlete but the information they had "did not provide reasonable suspicion that sexual abuse had occurred," the group said in a statement.
Ultimately, it was Nichols' report that prompted USAG to remove Nassar from "any further assignments."
USAG has denied Manly's assertion that the organization tried to keep the investigation secret ahead of the Olympics, saying it's "entirely baseless."
"We are sorry that any athlete has been harmed during her or his gymnastics career. USA Gymnastics is focused every day on creating a culture of empowerment that encourages our athletes to speak up about abuse and other difficult topics," the group said in a statement.
In a statement in December, USAG said it learned about the Maroney's lawsuit from media reports and that "the concept of confidentiality was initiated by McKayla's attorney, not USA Gymnastics."
Last week, USAG said it would not seek a fine if Maroney speaks publicly regarding sexual abuse she said she suffered at the hands of Nassar.
Bela and Martha Karolyi
•Why them? The famed coaches are not accused of direct involvement in the abuse scandal but scores of young gymnasts -- including Simone Biles, Aly Raisman and Maggie Nichols -- have said the Karolyi Ranch in Texas was one of the places where Nassar sexually assaulted and abused young athletes for years.
An ex-gymnast sued the Karolyis with USA Gymnastics, claiming they "turned a blind-eye to Nassar's sexual abuse of children," according to a 2016 complaint filed in Superior Court in Los Angeles County.
The gymnast, who is referred to as Jane LM Doe and was part of the US national team between 2006 and 2011, says she was abused by Nassar at the Karolyi-run facility that served as the training site for USA Gymnastics.
•What are the Karolyis saying? Bela Karolyi declined to comment when he was asked by CNN last Thursday if he knew about Nassar's abuse of the gymnasts at his facility.
•Kathie Klages retired in February from her job as MSU's head gymnastics coach. She had been suspended for defending Nassar, CNN affiliate WILX reported.
•MSU President Lou Anna Simon resigned after facing pressure over the way she handled the abuse scandal. Critics have called her tone deaf, saying she needed to be held accountable for what happened while Nassar was employed as a sports physician at the university from 1997 to 2016.
•NCAA is investigating MSU's handling of sexual abuse allegations against Nassar to determine if the university violated any rules.
•MSU physician Brooke Lemmen resigned last year. She allegedly removed "several boxes of confidential treatment records" from MSU at Nassar's request and didn't tell school officials that Nassar had told her in 2015 that he was being investigated by USA Gymnastics, the Lansing State Journal reported.
•Former USA Gymnastics CEO Steve Penny resigned last March. He reported Nassar to the FBI about five weeks after he became aware of the first complaint against the doctor in 2015, according to a timeline of events released by the organization.
•More USA Gymnastics resignations were announced Monday in a series of tweets from the organization's official Twitter account. Members of its board of directors executive leadership -- chairman Paul Parilla, vice chairman Jay Binder and treasurer Bitsy Kelley -- tendered their resignations, effective Sunday.
•United States Olympic Committee CEO Scott Blackmun called on all USA Gymnastics board members to quit and has threatened to decertify the group if it doesn't agree to his demands.
•USA Gymnastics is adopting dozens of new policies after a former prosecutor's lengthy report highlighted an array of shortcomings by USA Gymnastics in combating abuse. Changes include reporting suspected sexual misconduct to legal authorities and monitoring athlete housing.
•The Karolyi Ranch will no longer serve as the USA Gymnastics women's national team training center, the group announced last week. The Walker County Sheriff's Department says an active investigation is underway into the ranch, but declined to comment on the subject of the probe.
CORRECTION: This story has been updated to correct the spelling of US Olympic Committee CEO Scott Blackmun's name.