A lawsuit was filed Wednesday claiming officials at Michigan State University ignored early warning signs about school doctor and former USA Gymnastics team physician Larry Nassar, who was been accused of multiple sex crimes in recent months.

Nassar began working with the U.S. women's gymnastics team in 1986, and treated dozens of Olympic gymnasts as team doctor starting in 1996.

Former MSU softball player Tiffany Lopez, known then by her maiden name, Tiffany Thomas, claims Nassar sexually abused her regularly during medical exams beginning in 1998 and continuing over a period of three years.

"The Plaintiff, approximately 18 years old at the time, had a visit with Nassar where he touched her vagina," the lawsuit states, "in order to purportedly heal back pain she was having, under the guise of legitimate medical treatment. The Plaintiff complained to a trainer on her softball team who responded by saying Nassar was a world-renowned doctor, and that it was legitimate medical treatment."

The lawsuit, which claims both Nassar and Michigan State as defendants, goes on to describe further acts of sexual abuse, which Nassar's attorney has previously described as accepted medical procedures, according to ESPN.

Nassar has a series of civil and criminal cases against him pending, including his arrest on Friday for two counts of possessing and receiving child pornography. In October, a former 2000 Olympic gold medal-winning gymnast on the U.S. Women's National Team sued Nassar and USA Gymnastics, also claiming sexual abuse. Fifteen regional gymnasts in Michigan have also filed a notice of intent to sue both Nassar and Michigan State, all of which have made claims similar to those of Lopez.

The latest lawsuit comes on the heels of an investigation by the Indianapolis Star which reported that 368 gymnasts have alleged some form of sexual assault over the past 20 years in the U.S.