The University of California-Berkeley failed to investigate reports of serial rapists, took months to adjudicate sexual assault cases and dismissed rape threats as a joke, according to two federal complaints filed Wednesday by 31 current and former students.

The complaints against UC-Berkeley, alleging violations of the federal gender equity law Title IX, were filed with the U.S. Department of Education's Office for Civil Rights. The same group of students filed an additional Clery complaint against Cal, making similar claims that the university discouraged students from filing formal sexual assault charges, and frequently took months to begin an investigation when students did report the incidents.

One claimant, junior Sofie Karasek, told HuffPost that she was one of four women who met the school's Title IX administrators in April 2012 to report a male student who had sexually assaulted them in separate incidents. According to the complaint, university officials told the women that in order to file formal complaints they each needed to submit a written statement. After submitting their statements that spring, Karasek said, "There was no investigation. None of us were ever contacted."

Karasek followed up after the summer break to ask whether there would be any investigation or adjudication of the accused rapist. She said she received an emailed response in December 2012 telling her he had been punished, and would graduate that month. It wasn't until September 2013, Karasek said, that she learned he was found responsible for sexual misconduct and punished with probation and mandatory counseling.

Karasek said the women discovered they had been assaulted by the same man because he and they were all members of the same student organization. After learning of the assaults, the leader of the group attempted to eject the male student, but a university official allegedly responded that it would be better to keep him as a member because then "he would have a community of friends to process it" if he assaulted someone else, and they could help him realize it was wrong.

The university declined to comment on specific cases, citing privacy law.

"In terms of how long cases take, our aim is to conclude cases as quickly as possible but individual cases can vary based on issues such as the number of individuals involved, complexity of the case, availability of witnesses (who may be out of the country), and other issues," spokeswoman Janet Gilmore told HuffPost in an email.

An earlier Clery complaint, lodged against UC Berkeley in May 2013 , alleged that the university was underreporting sex crimes on campus and had failed to protect women. Those allegations spurred the California legislature in August to call for an audit of the school's sexual violence policies. The audit is still ongoing.

UC Berkeley Chancellor Nicholas Dirks, who took office last June, issued a campus-wide email Tuesday pledging full support for survivors and activists who want to address the issue of sexual assault on campus. Dirks also said the school would hire a new harassment investigator, a survivor advocate and a survivor resource officer.

"I believe we share a common goal for a campus where sexual assault is not present, tolerated or ignored," Dirks said.

Past Cases Brought Back To Light

The latest complaint includes testimony from 31 current and former students, some of whom attended the school as long ago as the 1970s. The former students and alumni say they are still haunted by what they feel is the mishandling of their cases.

Diva Kass was an undergraduate student at UC Berkeley in April 2009, when she says she was raped by the same male student on two occasions. After the second attack, Kass says she learned the student had assaulted another member of her sorority. Kass reported him in early May to the university.

Four months later, the university informed Kass it had scheduled a hearing to adjudicate the matter. In the interim, she says she faced an onslaught of harassment from the accused and his fraternity brothers. The university "acted with deliberate indifference" to those harassment reports, said Kass, now a law student at the University of Notre Dame.

At the hearing in October 2009, the accused was allowed to have an attorney present, was allowed to question Kass and to review the entire case file, but according to the complaint, the same was not afforded to Kass. She said she was not able to bring in witnesses from the night of the attacks and could not use testimony from the other alleged rape victim. Kass told HuffPost that the hearing panel asked her questions such as, "Why did you let it happen again?"

"It was viewed from this lens that, because it happened more than once, it couldn't have been rape," Kass said. "It was very clear people on the panel did not understand sexual assault ... or the law."

The panel found the student not responsible, and according to the complaint, Kass was not allowed to appeal. His fraternity had a party that night to celebrate the outcome of the judicial hearing, Kass said.

"I felt alone and helpless," Kass said. "It kind of made me feel like the university was okay with the fact that it happened to me and was just kind of putting on a charade."

The university spokeswoman did point out that the school's revised policy now allows victims to appeal hearing decisions.

Two former students involved in this week's filing were responsible for a Title IX complaint filed against the university in 1979 . In Wednesday's complaint they say they find the current handling of sexual violence at Cal to be "strikingly similar to those [concerns] that motivated our own Title IX complaint decades ago."

Falling On Deaf Ears

Stories of mishandled sexual assault cases have convinced some student victims that it isn't worth the trouble to report an assault, as was the case for sophomore Meghan Warner.

"When I looked at resources from the university online," said Warner, speaking of the time after her assault, "I saw that most were for the perpetrator, including an infographic for what to do if you're accused, not what to do if you are a survivor seeking help. This shocked and hurt me."

After she was sexually assaulted in Fall 2012, Aryle Butler said she inquired with the school's Gender Equity Resource Center about filing a formal complaint against her assailant, but was told it "would be too invasive and was encouraged not to."

When Butler later sought academic accommodations from professors due to stress she was experiencing in the wake of the assault, she said one responded, "I know students make things like this up" to get out of tests and difficult assignments. Butler would later be diagnosed with post-traumatic stress disorder.

Shannon Thomas, a sexual assault survivor, said, beginning in January 2014, she has faced ongoing harassment from a male peer, whom she reported to the university's Office for the Prevention of Harassment and Discrimination. In one incident, Thomas said, the male student threatened in a Facebook message to have "hate sex" with her. She asked the school to remove him from her class.

Thomas said that she was told by an OPHD case worker that he had met with the student who made the remark, that the student seemed "sincere and genuine" in his explanation that he was "simply joking," and the case worker would not recommend a "no contact" order between them.

"For a representative of this university to characterize threats of 'hate sex' as a laughing matter is beyond shocking, and completely unacceptable," a university dean wrote to the case worker in an email that Thomas provided to The Huffington Post.

"We're supposed to be making progress [dealing with sexual violence], and I felt like there was no progress made, as far as having policies that are not supportive and to have people that are supposed to be advocating on our behalf," Thomas said.

The Education Department's Office for Civil Rights currently has three dozen Title IX investigations open. The office has received 60 Title IX complaints in less than three years . If the department opens an investigation into UC Berkeley and finds the school at fault, it would likely recommend changes to policy and staffing through a resolution, or alternatively may refer the case to the U.S. Department of Justice.