Story highlights Aly Raisman is the second gymnast this week to speak out about Larry Nassar

Raisman says she's angry at the sport's governing body

(CNN) 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."

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