LANSING, Mich. (AP) — The NCAA is examining how Michigan State University handled the case of sports doctor Larry Nassar, who faces prison time for sexually assaulting Olympic gymnasts and other young female athletes.

Nassar worked at Michigan State and USA Gymnastics, which trains athletes aspiring to be Olympians. Former Spartans are among the more than 150 women and girls who have spoken over the last week at Nassar’s sentencing. Women’s gymnastics coach Kathie Klages resigned last year after she was suspended for defending Nassar over the years.

The NCAA sent a letter of inquiry to the school Tuesday “regarding potential NCAA rules violations related to the assaults Larry Nassar perpetrated against girls and young women, including some student-athletes at Michigan State.”

“Larry Nassar’s heinous crimes of record against more than 150 victims raise serious concerns about institutional practices, student-athlete safety and the institution’s actions to protect individuals from this behavior,” the NCAA wrote to Michigan State athletic director Mark Hollis.

The NCAA is asking the school to send information regarding any potential violations related to Nassar.

“To date, Michigan State has sent no information to the NCAA national office regarding Nassar’s actions,” the NCAA’s Oliver Luck, executive vice president of regulatory affairs, wrote in the letter.

Hollis, who has been Michigan State’s athletic director since 2008, responded today.

“Since my first day on the job as athletic director, my focus has always been on the student-athlete,” Hollis said. “They are at the core of our athletic department mission statement. Our first priority has always been and will always be their health and safety. In regards to the letter we received from the NCAA last night, the athletic compliance and university general counsel offices are preparing a comprehensive response. Michigan State University will cooperate with any investigation.”

Nassar, 54, pleaded guilty to assaulting seven people in the Lansing area, but the sentencing hearing has been open to anyone who said they were a victim. Under a plea deal, he faces a minimum of 25 to 40 years behind bars, although the actual punishment could be much higher. He already has been sentenced to 60 years in federal prison for child pornography crimes.