Survivors of convicted sports doctor Larry Nassar's sexual abuse began to find answers Tuesday as to how Michigan State University and its in-house lawyers allowed a notorious pedophile to abuse student athletes for two decades under the guise of treatment.

One key reason: Nassar's boss was allegedly in on it.

Special prosecutor William Forsyth Tuesday arraigned Nassar's former boss, William Strampel, on charges that include criminal sexual misconduct, willful neglect of duty and misconduct by a public official. Strampel served as dean of the MSU College of Osteopathic Medicine, where Nassar worked.

Strampel used his position “to harass, discriminate, proposition, sexually assault and solicit pornographic videos of female students,” according to an article in The Detroit News quoting investigators. He also used it to support Nassar against critics.

When an MSU in-house lawyer investigated Nassar in 2014 on a sex abuse complaint, Strampel backed both Nassar and the doctor's treatments as legitimate.

Now, The Detroit News said, investigators discovered pornographic videos on Strampel's work computer at MSU. They included at least one video of Nassar performing his purported “treatment” on a young female patient, according to a police affidavit.

Strampel's lawyer declined comment, the newspaper said.

Forsyth, the special prosecutor, was appointed in January by state Attorney General William Schuette to look into how MSU handled the Nassar crisis.

“What they [school trustees] wanted us to do was find out how MSU failed the survivors of Larry Nassar and how he was able to prey upon and victimize so many young women and girls for so long,” Forsyth said at a press conference. He said his investigation is ongoing.

Morgan McCaul, a Nassar victim, told The Detroit News she was happy that Strampel was being held accountable. “This is what survivors have been waiting for, for years,” McCaul said. “This man created an environment within the MSU osteopathic department in which the most prolific pedophile in sports history was allowed to thrive.”

Nassar, convicted of assaulting hundreds of young women, is spending the rest of his life in prison. Strampel, if convicted, faces up to eight years behind bars.

Strampel has been replaced as dean, but remains on the university's tenured faculty, although the school has begun proceedings to fire him.

He is also accused of failing to implement protocols put in place in 2014 to monitor Nassar.

The sexual scandal has led to hundreds of women filing ongoing suits against MSU, Nassar, Strampel and other school employees.

It also led to the resignations under pressure of former MSU president Lou Anna Simon and former general counsel Robert Noto, who failed to detect and resolve the issues before they exploded into a crisis.

Acting general counsel Kristine Zayko did not immediately return messages seeking comment on the arrest of Strampel. A year ago this month Zayko hired Maria Dwyer and her Detroit law firm, Clark Hill, to represent other MSU employees named as defendants in the Nassar victims' civil suits. But the contract excluded Strampel, even though he's a defendant.

Now Clark Hill's John Dakmak is representing Strampel on the new charges, but the university is not paying the legal fees.