(CNN)Attorney General Merrick Garland is facing more pressure to reconsider the Justice Department's decision not to bring any prosecutions related to the FBI's mishandling of the Larry Nassar investigation, with Iowa Sen. Chuck Grassley calling Friday for a federal prosecutor or special counsel to further investigate the matter.
"Nassar abused hundreds of young athletes while FBI sat on its thumb. DOJ refused to attend the Judiciary Committee hearing this week to face questions," Grassley said in a statement Friday. "Attorney General Garland should assign a federal prosecutor or special counsel to uncover what the FBI knew and when, as well as to seek prosecutions of those involved in the cover-up. These brave gymnasts and all Nassar survivors deserve accountability, especially from the Justice Department."
Asked by CNN for comment, the Justice Department said it has received and is reviewing the letter.
Justice Department Inspector General Michael Horowitz issued a scathing report about the FBI's Nassar probe failures in July. It singled out two former FBI officials for alleged false statements they made about the Nassar investigation, in addition to other violations of FBI protocols.
The IG report said that Horowitz's office had referred that conduct to the department for potential prosecution, but the department -- under both the Trump and Biden administrations -- had declined to bring charges. One of those FBI employees, Michael Langeman, was fired by the FBI in recent weeks, while the other, Jay Abbott, retired in early 2018.
At Wednesday's hearing, the gymnasts and lawmakers alike bashed DOJ's decision not to bring charges related to the botched probe.
"A message needs to be sent: If you allow a predator to harm children, the consequences will be swift and severe. Enough is enough," Olympic gymnast Simone Biles said.
In the period after the allegations against Nassar were reported to the FBI, some 70 athletes were abused by him while the investigation stalled out, according to the IG report.
"They allowed a child molester to go free for more than a year and this inaction directly allowed Nassar's abuse to continue," Olympic gymnast McKayla Maroney said.
This story has been updated to include a comment from the Justice Department.