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For more than two decades, Larry Nassar was regarded as one of the country’s premier sports medicine doctors as he treated numerous Olympic gold medalists and worked his way up the ranks at USA Gymnastics.

But as sentencing continues for Nassar inside a Lansing, Michigan, courtroom, dozens of girls and women are painting a very different portrait of the doctor - that of a serial sexual abuser who molested at least 140 athletes and tragically altered their life trajectories.

"I testified to let the world know that you are a repulsive liar and those 'treatments' were pathetically veiled sexual abuse," victim Kyle Stephens said to Nassar in court on Tuesday.

"Perhaps you have figured it out by now, but little girls don't stay little forever," Stephens added. "They grow into strong women that return to destroy your world."

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Former family friend to the Nassar family, and babysitter to Nassar's children Kyle Stephens, right, addresses Larry Nassar Tuesday, Jan. 16, 2018, during the first day of the victim impact statements addressing the former sports medicine doctor in Circuit Court Rosemarie Aquilina's courtroom in Lansing, Mich. (Matthew Dae Smith/Lansing State Journal via AP)

The 54-year-old Nassar – who is already serving 60 years in federal prison for child pornography crimes – faces between 40 and 125 more years behind bars after pleading guilty in November to molesting seven girls. Over the four-day sentencing, which began Tuesday, nearly 100 of Nassar’s victims are expected to address the court about the abuse they endured at the hands of the disgraced doctor.

Nassar joined the USA Gymnastics national team medical staff in 1986 as an athletic trainer and eventually became the team’s medical coordinator until 2015. He also ran a clinic and gymnastics club at Michigan State University, where he was a faculty member.

While accusations of abuse date back to 1994, it wasn’t until a September 2016 article in The Indianapolis Star reported allegations of abuse by two former gymnasts that actions were taken against Nassar. Following the allegations, Michigan State reassigned Nassar from his clinical and teaching duties before eventually firing him. Nassar claims that he retired from his role with USA Gymnastics, but the organization said it fired him in 2015 and notified law enforcement "after learning of athlete concerns."

Since the initial allegations were made public, more than 140 girls and women – including Olympic gold medalists McKayla Maroney, Aly Raisman, Gabby Douglas and Simone Biles – have accused Nassar of abuse.

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McKayla Maroney at the 2012 London Olympic Games. (The Associated Press)

“Dr. Nassar was not a doctor, he in fact is, was, and forever shall be, a child molester, and a monster of a human being,” McKayla Maroney wrote in her victim statement. “For me, the scariest night of my life happened when I was 15 years old. I had flown all day and night with the [U.S. gymnastics] team to get to Tokyo. He’d given me a sleeping pill for the flight, and the next thing I know, I was all alone with him in his hotel room getting a ‘treatment.’ I thought I was going to die that night.”

Raisman tweeted earlier this week that she would not attend the sentencing "because it is too traumatic for me. My impact letter will be read in court in front of Nassar. I support the brave survivors. We are all in this together."

In a statement posted on Twitter on Monday, Biles described Nassar's behavior as "completely unacceptable, disgusting, and abusive, especially coming from someone whom I was TOLD to trust."

According to the allegations, Nassar committed the sexual assaults under the guise of medical exams at his Michigan State University office, his home and a Lansing-area gymnastics club. The abuse ranged from inserting fingers in the gymnasts' vaginas and anuses, to fondling their breasts and genitalia. As part of plea deals in two adjacent Michigan counties, Nassar admitted his conduct had no legitimate medical purpose and that he did not have the girls' consent.

In a separate case, Nassar was sentenced last November to 60 years in federal prison for having received and possessed 37,000 images of child pornography and then attempting to destroy pictures to avoid charges.

Taking the stand on Tuesday, parent Donna Markham recounted how her 23-year-old daughter Chelsey killed herself in 2009, years after Nassar sexually abused her during a medical examination.

"It all started with him," she said, describing her daughter's downward spiral into drug abuse.

Larry Nassar

Defense attorney Shannon Smith talks to her client, Dr. Larry Nassar, during the second portion of his preliminary hearing on sexual assault at the 55th District Court in Mason, Mich. USA Gymnastics needs to undergo a “complete cultural change” to become better equipped at protecting athletes from abuse according to an independent review of the embattled organization’s practices. USA Gymnastics ordered the review last fall following a series of civil of lawsuits filed against the organization and the former team doctor by a pair of gymnasts who claim the physician sexually abused them during their time on the U.S. national team.(Julia Nagy/Lansing State Journal via AP)

Other victims described experiencing "searing pain" during the assaults and having feelings of shame and embarrassment. They said it had changed their life trajectories — affecting relationships, causing them to be distrustful and leading to depression, suicidal thoughts, and anger and anxiety about whether they should have spoken up sooner.

"He touched the most innocent places on my body," said 17-year-old Jessica Thomashaw, recounting how she was sexually assaulted at ages 9 and 12. "I couldn't be just a normal girl anymore, and I forever lost a big piece of my childhood due to his abuse."

Judge Rosemarie Aquilina consoled the 29 women and girls who spoke or had their statements read on Tuesday, saying they should not blame themselves. More victims are to speak on Wednesday and Nassar is expected to be sentenced Friday.

The Associated Press contributed to this report.