Star gymnast Aly Raisman on Wednesday accused USA Gymnastics of being "100% responsible" for former team doctor Larry Nassar's years of sexual abuse, saying in a series of tweets that the organization enabled him and manipulated athletes.

"STOP VICTIM SHAMING," the two-time Olympian wrote in a tweet, tagging USA Gymnastics. "Your statements are hurtful. If you did not believe that I & others were abused than why pressure & manipulate us?
"WE WERE MOLESTED BY A MONSTER U ENABLED 2 THRIVE FOR DECADES. You are 100% responsible. It was mandatory to get 'treatment' by Nassar."
.@USAGym STOP VICTIM SHAMING. Your statements are hurtful. If you did not believe that I & others were abused than why pressure & manipulate us? WE WERE MOLESTED BY A MONSTER U ENABLED 2 THRIVE FOR DECADES. You are 100% responsible. It was mandatory to get "treatment" by Nassar.
— Alexandra Raisman (@Aly_Raisman) January 10, 2018
Raisman's tweets come a day after Maggie Nichols, a former USA Gymnastics star, said she also was a victim of Nassar's abuse. Her attorney said the organization and others failed the victims and should be held accountable.
USA Gymnastics on Tuesday said it hired an independent investigator to look into Nichols' claim at the time and then reported it to the FBI. The organization said it never tried to hide Nassar's misconduct. "USA Gymnastics kept the matter confidential because of the FBI's directive not to interfere with the investigation."
Raisman, who has previously called out USA Gymnastics regarding Nassar's abuse, asked for more investigation into what is described as the largest case of sexual abuse in sports history.
"We must investigate to figure out the many flaws in @USAGym system. We must understand how this happened to make sure it never occurs again. This problem is bigger than Penny and Nassar. The system has to change so that athletes are safe. Enablers need to be held accountable," Raisman wrote.
We must investigate to figure out the many flaws in @USAGym system. We must understand how this happened to make sure it never occurs again. This problem is bigger than Penny and Nassar. The system has to change so that athletes are safe. Enablers need to be held accountable.
— Alexandra Raisman (@Aly_Raisman) January 10, 2018
If athlete safety is the number 1 priority for @TeamUSA & @USAGym , why don’t they want to know all the factors that contributed to the worst case of sexual abuse in the history of sports? #INVESTIGATE #WeNeedAnswers
— Alexandra Raisman (@Aly_Raisman) January 10, 2018
Nassar, the disgraced former doctor for Michigan State University and USA Gymnastics, admitted in court to using his trusted medical position to sexually assault underage girls.
As the national governing body of gymnastics in America, USA Gymnastics is responsible for training and selecting the US national gymnastics team. Nassar was the team doctor for USA Gymnastics through four Olympic Games. He also worked at Michigan State from 1997 to 2016 as an associate professor and the gymnastics and women's crew team physician.
In December, Nassar was sentenced to 60 years in prison after pleading guilty to child pornography charges. He is expected to be sentenced to more prison time next week after pleading guilty to first-degree criminal sexual conduct charges.
More than 140 women and girls have accused him of sexual misconduct, including Olympic gold-medalists Raisman, McKayla Maroney and Gabby Douglas.