Prosecutors in New York said on Monday that they have reopened an investigation into the alleged gang-rape of a student at Cornell University after an outcry over “leniency” shown to seven fraternity members named as the perpetrators.

According to lawyers for the student, who filed a civil lawsuit against the university and her alleged attackers earlier in September, only two members of the Chi Phi fraternity were expelled after the October 2024 incident, in which she said she was drugged and repeatedly raped over the course of seven hours.

None of the seven were arrested, they said, and the others were made to write essays, attend workshops or serve short suspensions.

On Monday, Matthew Van Houten, the Tompkins county district attorney, said his office was looking again at the case, after the woman, who was 20 at the time of the alleged assault, presented allegations in her lawsuit that were “dramatically different” from the statement she gave to police two years ago.

“It’s our intention to present the case to the Tompkins county grand jury with Jane Doe’s cooperation,” Van Houten told ABC News, using the name from the lawsuit to identify the woman.

“We want to re-examine whether there’s additional evidence that we were not aware of in November of 2024, that exists now that would change our assessment of the case and would result in the grand jury finding that there was criminal conduct.”

Outrage over the treatment of the alleged offenders has grown since the lawsuit was made public. The woman, who quit the university afterwards, said she went to visit a friend at the Chi Phi frat house in an already intoxicated state – and was made to snort a drug they told her was ketamine.

While they sexually assaulted her, she alleges, a message was sent to a frat house Snapchat group called Chi Phi Actives that stated there was “free pussy upstairs”.

At least five other frat members showed up and joined in, she said, and her ordeal lasted until about 5.45am. She made a report to campus police about three weeks later.

Cornell’s vice-president for university relations, Kyle Kimball, issued a statement on 21 September calling the allegations “deeply disturbing”. Kimball’s statement claimed the Ivy League institution’s offices of civil rights, student conduct and community standards carried out a number of inquiries at the time.

“The Xi chapter of Chi Phi fraternity remains barred from our campus,” Kimball’s statement also said. “Federal privacy law prohibits Cornell from disclosing specific information regarding individual students and we therefore are unable to make a public statement on any other disciplinary response.

“Violations of university policies could lead to sanctions up to and including suspension or expulsion. We will respond in detail through the legal process.”

An attorney for the student told CBS News that none of the alleged perpetrators faced legal consequences for their conduct, and nobody in the frat house that saw the message did anything to stop the rapes from taking place.

“Not one of these guys was arrested,” said the lawyer, Thomas Giuffra. “Not one. That I can tell you for a fact.

“There were so many people that could have prevented it and they didn’t. I’ve never seen anything like it.”

Giuffra also countered the statement of Van Houten, the Tompkins district attorney, which lays out what he said the alleged victim stated in her original police complaint from November 2024.

“She never says that she was drugged without her knowledge,” Van Houten said.

“She admits to taking drugs and alcohol voluntarily and with knowledge. She does not allege that she was forced to engage in any acts. She does not say that she was physically helpless or unconscious or incapacitated at any point during the time at the fraternity house.”

Giuffra told ABC News that neither the district attorney or Cornell police ever followed up with his client.

“In my experience, speaking with an abuse survivor requires delicacy, understanding and specialized training,” he said.

“An average university police officer would not have these skills. It would be the role of a specially trained detective or district attorney. However, Ms Doe was never contacted by anybody with those skills.”

On Sunday, the Academy Award-nominated actor Florence Pugh posted a lengthy statement on Instagram about Giuffra’s client, praising the “unbelievably powerful” victim and her “strong will”.

“This is really the moment where we need our men to be as horrified and as sickened as us,” Pugh wrote. “You need to be leading conversations about how we change the allowance and complicity of this behaviour as much as we are.”

• Information and support for anyone affected by rape or sexual abuse issues is available from the following organizations. In the US, Rainn offers support on 800-656-4673. In the UK, Rape Crisis offers support on 0808 500 2222. In Australia, support is available at 1800Respect (1800 737 732). Other international helplines can be found at ibiblio.org/rcip/internl.html