Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Six weeks after she focused the nation's attention on the U.S. Olympic Committee's bungled response to an enormous sexual-abuse scandal, gymnastics champion Aly Raisman is suing the embattled organization.

In court papers filed in California, the gold medalist contends the sports federation knew or should have known that team doctor Larry Nassar was molesting her and other young athletes under the guise of medical treatment.

Raisman is now one of more than 250 women and girls to sue Nassar and the organizations he worked with. One male gymnast, 18-year-old Jacob Moore, joined a massive federal suit this week, saying the doctor used acupuncture needles around his genitals for a shoulder injury.

Raisman's legal action comes days after the U.S. Olympic Committee, fresh off the Winter Games in South Korea, announced chief executive Scott Blackmun was stepping down because of a prostate cancer diagnosis.

If Olympic officials thought Blackmun's exit would mollify critics, they were wrong. In a statement, Raisman said the USOC and USA Gymnastics are stonewalling on the question of what they knew about Nassar's predatory behavior.

"After all this time, they remain unwilling to conduct a full investigation, and without a solid understanding of how this happened, it is delusional to think sufficient changes can be implemented," she said.

"I refuse to wait any longer for these organizations to do the right thing. It is my hope that the legal process will hold them accountable and enable the change that is so desperately needed.”

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

It was Raisman, a veteran of the 2012 and 2016 games, who turned up the heat on the Olympic Committee in January with a surprise appearance and searing statement at Nassar's marathon sentencing hearing.

"Why have I and the others here probably not heard anything from the leadership of the USOC? Why has the U.S. Olympic Committee been silent? Why isn’t the USOC here right now?" she asked.

Days later, the USOC apologized for skipping the hearing, pledged to reach out to the victims, ordered the board of USA Gymnastics to resign, and said it was launching an independent investigation conducted by a third-party.

Nassar's victims are skeptical that a review conducted by a law firm chosen and paid by the USOC can be truly independent. They are banking on Congress to get to the bottom of what Olympic and gymnastics officials knew.

The lawsuit describes how Nassar was allowed unfettered access to Raisman and other elite athletes as they trained at the Karolyi Ranch owned by famed coaches Bela and Martha Karolyi and at competitions around the world.

A USA Gymnastics trainer was sometimes in the room with Nassar as he penetrated the girls with bare hands for what he described as intravaginal therapy. Sometimes, he had an erection, the suit alleges.

A national team member, Maggie Nichols, reported the abuse to USA Gymnastics in the summer of 2015. But the group waited more than a month to alert the FBI and then failed to inform Michigan State University, where Nassar had his medical practice and continued to abuse girls until he was publicly exposed a year later.

"I refuse to wait any longer for these organizations to do the right thing."

The USOC said it only learned of the allegations against Nassar when The Indianapolis Star published a story about them in September 2016. But as NBC News reported last month, USA Gymnastics outlined the accusations in an email to the USOC's security chief a year earlier. A USOC spokesman has said the security official did not share the email with anyone else.

Even as the Olympic Committee has denied there was any cover-up, it has admitted that it "failed' the gymnasts preyed upon by Nassar.

Raisman's suit, which says she suffers from depression and anxiety, also named USA Gymnastics, the national governing body for the sport, which has insisted it had no inkling of Nassar's crimes until Nichols' report and kept the allegations secret because it believed the FBI wanted it that way.

But the lawsuit alleges that USA Gymnastics asked Nassar to stop constantly taking photos of gymnasts before Nichols' complaint and should have suspected he was a pedophile.

Nassar pleaded guilty in Michigan to molesting 10 girls and to possession of child pornography, and he is all but certain to spend the rest of his life behind bars.

Raisman, meanwhile, has morphed from athlete to activist, calling out Olympic bosses on her Twitter feed and appearing in the Sports Illustrated swimsuit issue with female-empowerment slogans written on her body.