SAO PAULO, BRAZIL - A female Brazilian student who was expelled from a Sao Paulo university after her short dress sparked student protests has been allowed back after federal prosecutors opened an investigation into the case.

The Universidade Bandeirante made the reversal after taking out advertisement space in Sunday newspapers to explain that it had expelled Geysi Villa Nova Arruda, 20, for her "incompatible posture with the atmosphere" at the school.

That decision, and video showing Arruda being hounded out by hundreds of students at the university, prompted a heated debate in the Latin American country known for its racy Carnival festivities and tiny bikinis but which also has a strong conservative streak.

The university, which had described the protests against Arruda in October as an act of "defense" by the student body, changed its stance on Monday after a federal investigation was launched.

Bandeirantes university had said that Arruda's expulsion was due to her behavior, saying she had acted provocatively by raising her dress, something she denied. She said she would return to the school to complete the academic year.

"In fact, I was very scared. I was the victim," O Globo newspaper on Tuesday quoted Arruda as saying. "I don't plan to change the way I am or the way I dress."

(Reporting Stuart Grudgings and Peter Murphy, Editing by Todd Benson and Will Dunham)