Warning: This story contains distressing details and discussion of sexual assault.

When Mary was a first-year college student, she woke up after a fraternity party with bruises and bite marks all over her body. She says it took her a few days to piece together that she had been sexually assaulted while “blacked out”, and to find the strength – and the right avenue – to report the assault.

The man she accused was eventually expelled, but police declined to bring charges because they said there was a lack of physical evidence.

Mary – whose name has been changed to protect her identity – says the process of finding some measure of justice was oftentimes confusing and disappointing.

“Even though it was a positive outcome, it was still so emotionally exhausting and draining, because I had to do all of this in tandem with getting used to being a college student for the first time,” said Mary. “In many ways, I had to be my own advocate, gathering all my evidence.”

The experience with local police, she added, “left me with a deep sense of disappointment in the system”.

How both universities and the criminal justice system respond to these types of assaults on college campuses is once again under the spotlight, after a former student at Cornell University filed a civil lawsuit alleging she was raped by several members of a fraternity two years ago, with prosecutors declining at the time to pursue a case.

Mary did not attend Cornell, and her case is not connected with the university. But advocates for survivors of sexual assault say her case, and the Cornell allegations, are emblematic of the larger challenges in responding to sexual assault claims on college campuses specifically.

The confusing web of systems and policies – which varies greatly by college – is one of several reasons why the vast majority of sexual assaults on college campuses, research suggests, go unreported.

“These processes are hard to navigate if you aren’t in trauma,” said Nancy Chi Cantalupo, an associate professor of law at Wayne State University who has represented victims on college campuses. “If you are in trauma, they’re virtually impossible to navigate.”

Earlier this month, the former Cornell student known only as Jane Doe filed a lawsuit against the Ivy League university, alleging she was drugged and raped by several men at a fraternity house at the university in 2024.

She also alleged that Cornell failed to protect her or adequately punish the men involved. Jane Doe said she had reported the alleged assault to campus police, who interviewed her, and provided information to the district attorney’s office. The prosecutor declined to bring charges at the time, but this week, Tompkins County District Attorney Matthew Van Houten re-opened the case.

Both Cornell and Van Houten have defended their handling of the 2024 case. In a statement, external, the university said it had “conducted an extensive investigation and adjudication over several months and imposed different sanctions based on the findings and circumstances involving each student” in addition to creating a new framework for addressing sexual assault on campus.

Cornell has said it followed the procedures outlined in a federal civil rights law called Title IX. The law mandates that universities follow certain rules about investigating sexual assaults. Cornell said its investigation resulted in the fraternity involved being barred from campus, and that students involved were suspended or expelled.

Typically, after a student reports an assault on campus, the university’s Title IX office determines whether the alleged behaviour could constitute a violation of policy.

Eventually, both parties attend a hearing with a panel of faculty members or other mediators to present evidence and testimony in the case before a decision by the school is reached.

One of the biggest challenges sexual assault survivors face is simultaneously navigating the university and the criminal justice system, which “serve different purposes, operate under different rules and timelines, and lead to different outcomes”, said Zoey Scheinblum-Brewer, a policy coordinator at the Rape, Abuse & Incest National Network, a nonprofit anti-sexual assault organisation.

“Unclear guidance about the options available through these parallel processes can create so much confusion and uncertainty that some students ultimately decide not to report,” she said.

Mary said this process at her college was not clear to her when she made the decision to report the assault.

“For me, it would’ve been nice to know what I was getting into before it all happened. It felt like they were learning the process alongside me,” she said of university officials.

While some colleges, like Cornell, have information sharing agreements with local police, Mary was told she had to go to police separately to file a report – a process she found physically exhausting.

Mary’s lawyer says there was surveillance footage from the night showing her alleged rapist carrying her “slumped” over, and she had pictures of her bruises and bite marks. But police told Mary they did not have probable cause for an arrest, and that the district attorney wanted to leave it to university administration.

“I was left with this taste that because they knew that the college was ‘handling’ my investigation, that they could wipe their hands clean of it,” she said.

The local police department told the BBC it did not have the details of this particular case. The local district attorney’s office did not respond to a request for comment.

University investigations are done behind closed doors, said Helene Weiss, a lawyer who has represented several victims of sexual assault on college campuses. She believes that part of the reason for the secrecy is to protect institutions’ reputations.

“The secrecy of the process, it prevents other students from knowing about it. It prevents witnesses from coming forward,” she said.

Michael Diamondstein, a Pennsylvania attorney who has represented those accused of sexual misconduct on college campuses, said the secrecy helps protect both the victim and the accused.

“I think when you compare it to what they would face in a courtroom, it’s much easier for students and much safer for students. Their name isn’t put out there. The news media doesn’t get them,” he said.

Cornell students have criticised the university’s handling of the woman’s claims. The Cornell Daily Sun, a student newspaper, published the names of the accused under the headline: “Cornell won’t, we will.”

In a statement, the college said that federal privacy law “prohibits Cornell from disclosing specific information regarding individual students” so it cannot “make a public statement on any other disciplinary response”.

Many advocates say there is merit to universities investigating sexual assault complaints separately from the criminal justice system. Prosecuting sexual assault cases is notoriously difficult – a recent systematic review found that less than 10% of sexual assault cases yielded convictions. In a criminal trial, a prosecutor must convince a jury “beyond reasonable doubt” that the accused is guilty. But in a campus tribunal, the burden of proof is lower.

Under Title IX, the university is also required to offer solutions that local law enforcement cannot, like ensuring a student is not in the same class as their alleged abuser while the investigation is ongoing and offering homework extensions, said Scheinblum-Brewer.

This is one of several reasons why victims and advocates for survivors say there are benefits to having two separate avenues, through the university and the criminal justice system.

For Mary, after her case was dropped by the police, pursuing her assault claim through Title IX became the only way for her alleged rapist to face repercussions: an expulsion from college.

“This was my only avenue to achieve any sort of justice,” she said.