Updated

Former U.S. Olympic women's gymnastics team coach John Geddert is facing a criminal investigation following the final sentencing of disgraced ex-sports doctor Larry Nassar, who molested girls at Geddert's elite gymnastics club in Michigan.

The Eaton County Sheriff's Office said Tuesday that people recently came forward with complaints against Geddert, 60. The office declined to elaborate on the number of complaints, when exactly they were filed or their nature, citing the ongoing investigation.

Geddert until recently owned and operated Twistars, a gym in Dimondale near Lansing where Nassar offered treatments on Monday nights. During Nassar's two recent sentencing hearings, some victims complained that Geddert was physically abusive, was indifferent to injuries and forced them to see Nassar.

One also alleged that Geddert was aware in the late 1990s that Nassar had performed an "inappropriate procedure" on her when she was 16, and her mother and Geddert agreed that Nassar would not treat her in private appointments again. That accuser's anonymous statement was read in court by a prosecutor.

The Associated Press left a message seeking comment with Geddert's lawyer Tuesday.

Geddert has insisted he had "zero knowledge" of Nassar's crimes. In response to lawsuits, his attorney filed court papers saying Geddert was "just one person in an extremely long line of people who were fooled by Nassar."

Geddert previously was accused of physically assaulting a Twistars employee in 2011. He also was accused of assaulting a gymnast in 2013. He did not face charges in either case.

On Monday, the worst sex-abuse case in sports history ended with a third long prison sentence for Nassar — this time 40 to 125 years for molesting young gymnasts at Twistars. The focus will shift to civil lawsuits and multiple probes of Nassar's actions and those of people around him when he worked for Michigan State University and USA Gymnastics, the sport's governing body.

Geddert, whose national profile rose while training Lansing-area standout Jordyn Wieber, was suspended last month by USA Gymnastics until it completes its own investigation. Geddert coached the "Fierce Five" that won a team gold in 2012 in London. He recently announced his retirement and transferred ownership of the club to his wife, Kathryn.

A spokeswoman for Michigan Attorney General Bill Schuette, whose office prosecuted Nassar, has declined to say if Geddert or Twistars is under investigation

An astonishing 250-plus women and girls gave statements in two Michigan courtrooms over 10 days of proceedings.

Makayla Thrush, who trained at Geddert's club from ages 7 to 17, said she developed an eating disorder because of Geddert and accused him of becoming so angry that he threw her on top of a low bar, ruptured the lymph nodes in her neck, gave her a black eye and tore the muscles in her stomach, ending her career.

"I have been dealing with many mixed emotions the past few weeks, some of it having to deal with the enablers of the abusers trying to get out of their screw-up," she said in court last month. "There isn't one bone in my body that doesn't hate John Geddert for everything he has done to me in my career."

Separately Tuesday, Michigan State released a letter that interim president John Engler sent Monday to an independent special prosecutor appointed by state Attorney General Bill Schuette to investigate allegations that the school ignored and mishandled old complaints against Nassar.

Engler pledged "full cooperation" but also criticized William Forsyth for sending authorities without warning to execute search warrants at the university Friday, as news cameras filmed. Engler noted that Schuette had said the probe would not be "political."

The presence of camera crews was hopefully "not part of an investigation 'media strategy' but rather inadvertent and the result of indiscrete behavior that can be stopped," Engler wrote. Leaks must be prevented, he said.

"Your credibility depends on that, as does the MSU community's need for a report that is viewed as objective and complete. We owe this to the survivors," he wrote.

A spokeswoman for Schuette, who is running for governor and whose campaign has been endorsed by Engler — himself a former Republican governor — said the letter was being reviewed.

Also Tuesday, a spokeswoman for Republican Gov. Rick Snyder said Michigan State Board of Trustees Chairman Brian Breslin, who is also Snyder's appointments manager, began an unpaid leave of absence for between 30 and 90 days from that job to focus on his post with the trustees.

"While the two roles never overlapped, my first priority is to fulfill my statewide elected responsibilities as a MSU Trustee," Breslin said in a statement.