More than 90 women who say they were sexually assaulted by Lawrence G. Nassar, the former doctor for U.S.A. Gymnastics who was convicted on state sexual abuse charges, filed lawsuits on Wednesday against the F.B.I. for its failure to investigate him when it received credible information about his crimes. The lawsuits come two weeks after the Justice Department decided not to prosecute two former F.B.I. agents accused of bungling the bureau's 2015 investigation into Mr. Nassar, allowing him to assault more than 70 girls and women for over a year before Michigan authorities arrested him. The agents were accused by the Justice Department's own watchdog of making false statements about the matter. In the fall, Christopher A. Wray, the F.B.I. director, testified to Congress that "there were people at the F.B.I. who had their chance to stop this monster back in 2015 and failed." The plaintiffs include the Olympic gymnastics gold medalists Simone Biles, Aly Raisman and McKayla Maroney. "My fellow survivors and I were betrayed by every institution that was supposed to protect us " the U.S. Olympic Committee, U.S.A. Gymnastics, the F.B.I. and now the Department of Justice," Ms. Maroney said. "It is clear that the only path to justice and healing is through the legal process," she added. Mr. Nassar, who was sentenced to up to 175 years in prison, was accused of molesting hundreds of girls and women, including many members of the 2012 and 2016 U.S. Olympic gymnastics teams.