Michigan State University has been stonewalling investigators tasked with getting to the bottom of the school's mishandling of sexual abuse carried out by Dr. Larry Nassar, prosecutors said Friday.

Special counsel Bill Forsyth blasted MSU for allegedly trying to sabotage the state-ordered probe, which comes in the wake of Nassar's conviction for decades of sex crimes he committed while working in East Lansing.

“Their biggest concern was the reputation of the university,” Forsyth told reporters in Lansing.

Forsyth's report,released Friday as an update on the investigation, specifically accused the school of "drowning investigators in irrelevant documents," "waging needless battles over pertinent documents" and "asserting attorney-client privilege even when it did not apply."

"Both then and now, MSU has fostered a culture of indifference toward sexual assault, motivated by its desire to protect its reputation," according to Forsyth's report.

The school employed a "protectionist tactic," designed to slow the probe, prosecutors said. Requests for documents were often answered with papers — such as the school bed bug policy, local restaurant coupons and publicly available newspaper clippings — that had nothing to do with Nassar, the report claimed.

In one email, prosecutors found that Heather Swain, MSU's vice president for communications, told a trustee to copy in the university's attorney just so the thread could be hidden from investigators.

"From just the emails that MSU voluntarily disclosed, investigators caught a glimpse into MSU's culture of anti-transparency," the report said of Swain.

Swain did not immediately return messages seeking comment.

Victims and supporters look on as Rachael Denhollander speaks at the sentencing hearing for Larry Nassar in Lansing, Michigan, on Jan. 24, 2018. Brendan McDermid / Reuters file

MSU's counsel office declined comment on Friday and referred all calls to Emily Gerkin Guerrant, the school's vice president and primary spokesperson.

Guerrant insisted that MSU has been cooperating fully with the special counsel. She also said that any school documents, that could fall under lawyer-client privilege, have been turned over to a third-party judge, who has ruled whether those papers are protected from prosecutors.

"We have cooperated the entire investigation, and will continue to do so if more factual information is needed," Guerrant said in a statement to NBC News. "We are committed to working with appropriate authorities to understand fully the entire Nassar case."

The special counsel's report went on to name nearly a dozen MSU employees who learned of Nassar's abuse from the victims themselves. It said employees were aware of the abuse allegations as far back as 1998 and as recently as 2015. But in nearly every case, the employees — who included coaches, athletic trainers, fellow doctors and the school Title IX office — did nothing, prosecutors said.

Only Dr. Jeffrey Kovan, team doctor for Michigan State's basketball, soccer, track and softball programs, was named by Forsyth as having properly reported Nassar to the MSU's Title IX office.

"The MSU employees who allegedly received reports of Nassar's sexual assault or improper medical treatment (with the exception of Dr. Kovan) downplayed its seriousness or affirmatively discouraged the survivors from proceeding with their allegation," the report said.

Hundreds of women and girls, almost all gymnasts, said Nassar sexually assaulted them while treating them on behalf of his employers, Michigan State and USA Gymnastics.

In 2017, Nassar was sentenced to 60 years in prison after pleading guilty to federal child pornography charges. And earlier this year, he was sentenced to 40 years to 175 years in a Michigan state prison after pleading guilty to seven counts of sexual assault of minors. He was then sentenced to another 40 to 125 years in a separate case.

Forsyth and his team prosecutors and investigators have already brought criminal charges against five people, including ex-Michigan State President Lou Anna Simon, former Dean of the College of Osteopathic Medicine William Strampel and former MSU gymnastics coach Kathie Klages.

Forsyth, who was appointed by Michigan Attorney General Bill Schuette to investigate MSU’s handling of Nassar, said his investigation is ongoing.