"You can't touch us @LarryNassar," read the banner that hung out of the window at the Psi Upsilon Brotherhood on Saturday.
The gymnast became aware of the sign after seeing people condemn it on Twitter. She tweeted that it was "incredible" for someone to hang such a sign.
"This type of thing makes my stomach worse. I hope the school makes the right measurements to look into this, "she said.
The sign was later removed, according to a statement by the University of Michigan.
"The leadership of the local head of the Psi Upsilon Brotherhood took immediate action to remove the flags on Saturday and the University Brotherhood and Fear Service immediately contacted the President of the Chapter and Counselors," said University of Michigan spokesman Rick Fitzgerald. "The head will take corrective action with those responsible for hanging the banners and those who have failed to intervene."
Members of the university's community also filed complaints against the fraternity with the Greek activity review panel, Fitzgerald said.
Psi Upsilon did not return calls or emails to CNN for comment.