The scandal surrounding Nassar was unfolded several years ago, when he was accused by more and more gymnasts of sexual abuse.
He has been serving a long prison sentence since 2018.
Earlier this summer, the federal police's way of conducting the investigation into Nassar received scathing criticism from the Ministry of Justice's investigator Michael Horowitz.
The FBI's office in Indianapolis did not take the charges against Nassar "with the utmost seriousness and urgency that they deserved and demanded."
The FBI was negligent
That is what Horowitz wrote in his report.
He also said that the FBI's negligence led to Nassar being able to continue with his crime.
Simone Biles, McKayla Maroney, Maggie Nichols and Aly Raisman are among the most prominent gymnasts called to the Senate Committee.
The four, out of hundreds of victims, were all abused by Nassar.
Chris Wray, the FBI's chief of staff, has also been summoned to a meeting with representatives of the Senate.