DETROIT — Thirteen sexual assault victims of Larry Nassar are seeking $10 million each from the FBI, claiming a bungled investigation by agents led to more abuse by the sports doctor, lawyers said Thursday.

Larry Nassar Matthew Dae Smith/Lansing State Journal via Associated Press

It’s an effort to make the government responsible for assaults that occurred after July 2015. The Justice Department’s inspector general concluded that the FBI made fundamental errors when it became aware of allegations against Nassar that year.

Nassar was a Michigan State University sports doctor as well as a doctor at USA Gymnastics. He is serving decades in prison for assaulting female athletes, including medal-winning Olympic gymnasts.

“This was not a case involving fake 20 dollar bills or tax cheats,” attorney Jamie White said. “These were allegations of a serial rapist who was known to the FBI as the Olympic U.S. doctor with unfettered access to young women.”

Nassar, he added, continued a “reign of terror for 17 unnecessary months.”

Indianapolis-based USA Gymnastics told local FBI agents in 2015 that three gymnasts said they were assaulted by Nassar. But the FBI did not open a formal investigation or inform federal or state authorities in Michigan, according to the inspector general’s report.

Los Angeles FBI agents in 2016 began a sexual tourism investigation against Nassar and interviewed several victims but also didn’t alert Michigan authorities, the inspector general said.

“No one should have been assaulted after the summer of 2015 because the FBI should have done its job,” said Grace French, founder of a group called The Army of Survivors. “To know that the FBI could have helped to avoid this trauma disgusts me.”

White is not suing the FBI yet. Under federal law, tort claims must be a filed with a government agency, which then has six months to reply. A lawsuit could follow, depending on the FBI’s response.

The FBI declined to comment Thursday but referred to Director Christopher Wray’s remarks to Congress about how the matter was poorly handled.

“I’m sorry that so many different people let you down, over and over again,” Wray told victims at a Senate hearing last year. “And I’m especially sorry that there were people at the FBI who had their own chance to stop this monster back in 2015 and failed. And that’s inexcusable. It never should have happened.”

White said more than 100 women were assaulted after July 2015, and he expects other lawyers will file claims against the FBI. Nassar wasn’t arrested until November 2016 during an investigation by Michigan State University police.

The Michigan attorney general’s office ultimately handled the assault charges against Nassar, while federal prosecutors in Grand Rapids, Michigan, filed a child pornography case.

White noted the 2018 massacre at Florida’s Marjory Stoneman Douglas High School. The FBI received a tip about five weeks before 17 people were killed at the school, but the tip was never forwarded to the FBI’s South Florida office. The government agreed to pay $127.5 million to families of those killed or injured.

Michigan State University, which was also accused of missing chances over many years to stop Nassar, agreed to pay $500 million to more than 300 women and girls who were assaulted. USA Gymnastics and the U.S. Olympic and Paralympic Committee made a $380 million settlement.