An investigation into the FBI's failure to deal with Larry Nassar sooner is underway.

Gymnasts Simone Biles, Aly Raisman, McKayala Maroney and Maggie Nichols will appear at the US Senate to testify about the FBI's handling of convicted sex offender Larry Nassar. Nassar worked as a doctor for the US gymnastics team and used his position to abuse numerous young girls and women. In 2017, after pleading guilty to possessing child sexual abuse imagery and tampering with evidence, Nassar was sentenced to 60 years in a federal prison. A few months later, he was sentenced to an additional 40-175 years in Michigan State Prison after pleading guilty to seven counts of sexual assault of minors. He subsequently was sentenced to 40-125 years in prison after he pleaded guilty to three counts of sexual assault. The testimony of the elite gymnasts will form part of the US Senate's investigation into why the FBI failed to investigate Nassar sooner. Earlier this summer, Justice Department Inspector General Michael Horowitz released a report which detailed how Nassar's abuse was allowed to carry on for as long as it did. FBI Directory Chris Wray is expected to testify and face questioning over why the agents who botched the probe over Nassar were not prosecuted for doing so. The FBI began investigating allegations made against Nassar after the USA Gymnastics President Stephen Penny reported them in 2015. Mr Penny also provided the agency with the names of three victims who were willing to talk about the abuse. However, the office did not open a formal investigation. The FBI only interviewed one victim months later and they failed to formally document the interview until 2017. By this time, Nassar had already been arrested on child sexual abuse image charges. When the interview was finally filed, Mr Horowitz's report found that it was filled with "materially false information and omitted material information".