The plaintiffs alleged a pattern of sexual abuse, disguised as treatment, that began in the late 1990s and continued into 2016. Most of the girls were teenagers at the time of the alleged assaults, although several were as young as 9.
Nassar, 53, is already facing state and federal criminal charges, including sexual assault with a person under 13 and possession of child pornography.
CNN reached out to Matt Newburg, Nassar’s attorney in the criminal cases, who said he does not represent him in the civil case. It could not be immediately determined whether Nassar has retained an attorney in the civil suit.
Seventeen of the plaintiffs in the civil suit, filed Tuesday, have chosen to remain anonymous. The other, Rachael Denhollander, says she was assaulted by him repeatedly at Michigan State in 2000, when she was 15 and seeking treatment for wrist and back pain.
“The decision to pursue civil charges was painful and it was difficult. It is a decision to continue to be immersed in these events on a national scale, for an extended period of time,” Denhollander told reporters at a press conference Tuesday in Grand Rapids, Michigan.
The victims in the lawsuit are or were athletes in a variety of sports, including gymnastics, swimming, figure skating, track and field, field hockey, basketball, and soccer.
Also listed as defendants in the suit were USA Gymnastics, the national governing body for the sport, with whom Nassar was affiliated from 1996 to 2015; Michigan State University, where Nassar worked from 1996 to 2016; and Twistars USA, a Michigan gymnastics facility where Nassar also worked.
Nassar was the team doctor for the Michigan State University gymnastics and women’s crew teams, an associate professor in MSU’s College of Osteopathic Medicine and a physician for the US national gymnastics team through four Olympic Games.
The lawsuit alleges that USA Gymnastics, MSU and Twistars were negligent in allowing the abuse to occur, and that Michigan State kept Nassar on its staff even though at least three of his patients had filed complaints about his behavior.
The suit claims that MSU investigated one of the alleged victims’ complaints in 2014 but dismissed them after determining that the victim “didn’t understand the ‘nuanced difference’ between sexual assault and an appropriate medical procedure.”