John Geddert, who was the U.S. women's gymnastics coach for the gold-medal-winning 2012 Olympic team in London, has been suspended by USA Gymnastics until it completes an investigation, the governing body announced Monday.

Geddert, the most decorated women's gymnastics coach in Michigan history, has operated two gyms that employed Larry Nassar, the disgraced Michigan State University and Olympics doctor who is accused of sexually assaulting more than 150 girls and young women. Nassar, 54, pleaded guilty in November to 10 counts of first-degree criminal sexual conduct with victims as young as 6 years old. His sentencing hearing, which began last week, continues this week. Dozens of women and girls have read victim-impact statements about the abuse they suffered by Nassar.

"John Geddert has been suspended under the interim measures provisions of Section 10.5 of USA Gymnastics' Bylaws. USA Gymnastics is unable to comment further as this is a pending matter," the governing body said in a statement.

Section 10.5 states that interim measures may be imposed "to ensure the safety and well-being of the gymnastics community or where an allegation is sufficiently serious that an Adverse Party's continued participation could be detrimental to the sport or its reputation."

Geddert can request a review of his suspension; he did not respond to requests for comment.

Geddert's most accomplished athlete is Jordyn Wieber, a member of the famous "Fierce Five," the gold-medal-winning team from the 2012 London Olympics. Wieber on Friday told an Ingham County, Michigan, judge that she too was sexually assaulted by Nassar, the first time she had publicly revealed the abuse.

A story by Outside the Lines last week detailed the ties between Nassar and Geddert.

Over the past 25 years, the two have been all but inseparable, professionally and socially, according to the story. They worked together first at Geddert's Great Lakes Gymnastics Club and then, starting in 1996, at the gym Geddert owns now, Twistars USA Gymnastics Club near East Lansing, Michigan. They worked the 2012 Olympics together. Geddert was in Nassar's wedding party when Nassar got married in East Lansing in 1996. They attended each other's house parties and traveled the country and, later, the world together at competitions. They vouched for each other when faced with career-threatening circumstances.

Geddert, who took his Twistars team to the Sand Dollar Invitational in Plant City, Florida, this past weekend, was suspended Friday, according to sources who spoke with Outside the Lines. He stayed through the weekend but watched the competition from the crowd.

Many survivors of Nassar's have been highly critical of USA Gymnastics over the organization's handling of complaints against Nassar. On Sunday, several USAG board members resigned, including the chairman, Paul Parilla. Also resigning were vice chairman Jay Binder and treasurer Bitsy Kelley.

John Geddert, who coached the 2012 U.S. Olympics gymnastics team in London and spent more than two decades working alongside Larry Nassar, has been suspended by USA Gymnastics, the sport's governing body. Kyle Terada/USA TODAY Sports

"We support their decisions to resign at this time," USAG president Kerry Perry said in a statement. "We believe this step will allow us to more effectively move forward in implementing change within our organization."

Geddert's coaching style has largely been based on fear and intimidation, according to dozens of people who spoke with Outside the Lines over the past year, a group that includes current and former gymnasts, parents of gymnasts, coaches who have worked alongside Geddert and other gym employees. Many of those contacted said they were reluctant to speak publicly about Geddert because they either have children involved in gymnastics in the Lansing area or careers in the sport and they are mindful of the power he wields.

Geddert joined Great Lakes as head coach in 1984 and helped build the gym into a national powerhouse. In the workout area, he frequently could be overheard screaming at his gymnasts, reducing many to tears. He threw things. He routinely denied gymnasts water until they performed exercises to his satisfaction, former gymnasts said.

In the hyper-competitive environment in which the fiery head coach lorded over the gym, Nassar's training room at Great Lakes offered an escape, former gymnasts told Outside the Lines. It was tucked behind the vault and balance beam, through a heavy metal door with a single small window that Nassar often covered with a sheet while treating gymnasts. A parent would have had to walk across the entire workout floor to get to the training room, and few ever did.

"John and Larry were like this perfect storm," said a former office manager of Geddert's at Twistars, Priscilla Kintigh, who was coached by Geddert at Great Lakes in the mid-1980s and whose son trained at Twistars. "You become so unapproachable that your own gymnasts don't feel comfortable telling you what's going on. There's no way any of the girls would have felt comfortable saying anything to John [about Larry]. Kids were terrified of him."

Amanda Smith, who trained at Twistars starting at age 9 in the early 2000s, gave an impact statement in court on Monday morning during Nassar's sentencing that detailed some of Geddert's behavior.

In an interview outside of the courtroom, Smith said she watched Geddert regularly shove and berate girls in the gym, punishing them for failures in courage by forcing them to do hours of physical conditioning. Twistars' work with male gymnasts was being phased out in the early 2000s, which left the boys' locker room empty most days. Smith said it became the place where Geddert pulled gymnasts aside to verbally abuse them.

"That was a daily thing," Smith said. "It was like Dr. Nassar had the back room, and [Geddert] had the locker room. We were terrified to go in there. Even if you didn't know what happened in there, it was very clear when girls came out and were hyperventilating because they were so scared."

Nassar started working with Geddert at Great Lakes the same year he started medical school at Michigan State. By then, Nassar was an accomplished athletic trainer who had volunteered at the 1987 Pan American Games and 1988 Olympic gymnastics trials, treating members of the U.S. women's national team. One time, with his medical school future in doubt, it was Geddert who came to Nassar's aid, writing a letter to the dean of Michigan State's College of Osteopathic Medicine.

In the years that followed, Nassar and Geddert rose to greater prominence within the gymnastics world. In 1996, Nassar became national medical coordinator for the sport's governing body, USA Gymnastics, a position that made him part of an iconic Olympic moment that same year: He helped Team USA gymnast Kerri Strug to the bench during the Atlanta Games after she was injured on the vault.

Geddert served as head coach of the women's team at the London Games. In recent months, three members of that team in addition to Wieber -- Aly Raisman, McKayla Maroney and Gabby Douglas -- have alleged that they too were sexually assaulted by Nassar under the guise of medical treatment.

In the months before and after the London Olympics, Geddert's temper threatened his career. He was accused of assault and battery in two separate incidents at Twistars, according to police reports obtained by Outside the Lines. In the first incident, reported in November 2011, the parent of a Twistars gymnast, who also worked at the club as a coach, told state police that during a heated argument after an evening practice, Geddert followed her into the parking lot and physically assaulted her by stepping on her foot and chest bumping her to prevent her from leaving. In the second incident, a year later, a gymnast told police Geddert "stepped on her toe, grabbed her arm and pushed her into the wall" to discipline her, according to a police report. Geddert, who told police the 11-year-old "got her ass chewed," denied the allegations of assault, and he did not face charges in either case.

Shortly after the second alleged incident, the girl's grandmother received a series of text messages from an unexpected source -- Larry Nassar. He pleaded with her not to file charges against Geddert.

Nassar went on to say in the texts, which were reviewed by Outside the Lines: "John just sent a policy out that from now on all staff members are not to be allowed to be with a gymnast alone and not allowed to be in any room without the door being open."

Whether such a policy ever existed at Twistars is unclear, but if it did, it didn't apply to Nassar. Just as he had years earlier at Great Lakes Gymnastics, Nassar saw hundreds of girls on his training table in a back room at Twistars, alone. Parents would sign up their children to see Nassar on Monday evenings and often wait more than two hours for a chance to be treated by him. Dozens of former Twistars gymnasts now say Nassar sexually abused them during those medical exams.

In the spring and summer of 2014, USA Gymnastics paid Don Brooks, a Lansing private detective, to investigate the history of complaints against Geddert. Among others, Brooks interviewed the former Twistars gymnast who alleged Geddert assaulted her in the locker room, the girl's grandmother said. When reached by phone, Brooks declined to comment about his findings, which he turned over to USA Gymnastics in September 2014. It's unclear what happened to the investigation; USA Gymnastics declined to comment.

Nassar was well aware of the way Geddert worked with gymnasts. What's not clear, even today, is how much Geddert knew about Nassar's serial sexual abuse. On at least one occasion, Geddert walked into the back room of Twistars while Nassar was digitally penetrating a young gymnast, according to the woman's court testimony: "All I remember is him [Nassar] doing the treatment on me with his fingers in my vagina, massaging my back with a towel over my butt, and John walking in and making a joke that I guess my back really did hurt."

One former gymnast of Geddert's told Outside the Lines that the dynamic in Geddert's gym led her to conclude that "part of what enabled this is John broke little girls' spirits and bodies, and Larry was there to fix them."

ESPN staff writer Dan Murphy contributed to this report.