(NewsNation) — The first known victim of convicted child abuser Larry Nassar says that federal agencies, including the FBI, swept allegations of sexual abuse among young girls under the rug and allowed at least 100 more victims to suffer at Nassar’s hands.

Sarah Klein, a former competitive gymnast who is now an attorney and advocate for sexual assault victims, told “Elizabeth Vargas Reports” that she had very mixed feelings when the Department of Justice announced a $137.7 million settlement agreement with 139 of Nassar’s victims this week.

In the settlement, the DOJ acknowledged the FBI failed to conduct an adequate investigation into the former team doctor when initial claims were made.

In a statement, the DOJ said that for decades, Nassar abused his position and betrayed the trust of those in his care and medical supervision while skirting accountability. Among those who made claims were Olympic gold medalist Simone Biles.

Klein said she had mixed feelings about the settlement by the Department of Justice. She said that part of her felt a “profound sense of relief”after victims had to tell their stories hundreds of times, making them feel like they were involved in a “constant war”, Klein said.

“On one hand, we’re happy that it’s over, and we’re grateful for legal closure,” Klein said Friday. “But on the other hand, there’s a real sense of, I would call it, a profound sadness in what will be remembered, in my opinion, as one of the darkest eras in the history of sport.”

Nassar was sentenced to 60 years in prison for child pornography but will serve an additional 40 to 175 years for sexually abusing children.

More than 500 women and girls suffered abuse at the hands of Nassar, but Klein says that when a serial pedophile has worked for these institutions for the better part of 30 years, the “math” of the number of victims is going to begin to increase.

In many cases, Klein said, the FBI failed to pick up the phone and call Michigan State University, where Nassar was working, to investigate allegations of abuse. Instead, gymnasts like Biles were forced to testify in front of Congress and “sacrifice themselves” while reliving their trauma with Nassar, which Klein says will leave a permanent scar on his victims.

That, Klein said, falls on the FBI’s failure to act.

“When there is an incentive to throw the kids under the bus and sweep it under the rug, that’s what certain people with certain levels of character apparently will do,” Klein said.