An investigation of the Sigma Alpha Epsilon fraternity ensued after anonymous reports were filed about the sexual assault and potential drugging of as many as four females, according to Chicago Tribune reporters Stacy St. Clair and Gregory Pratt.

According to the report, it was not clear how the person that reported the incidents knew about the alleged attacks. The claims against the Sigma Alpha Epsilon fraternity were filed after an event on January 21. Not long after, another anonymous report was filed about a second fraternity, but the school has not publicly named that house.

The identities of the four women involved were unknown, according to Northwestern spokesman Bob Rowley. Despite the unknowns in the case, the University shared the information with faculty and students in accordance with federal law.

The level of transparency the University maintained when releasing this information resonated with students as “unprecedented,” and received praise from students for “taking sexual assault allegations seriously.”

A statement was released by SAE chapter president, Manos Proussaloglou, that “pledged cooperation with the university’s investigation.”

No criminal investigation was opened due to lack of witnesses.