Members of a feminist group at the University of Mary Washington on Thursday filed a complaint against the school with the US Department of Education, accusing the university of failing to adequately prevent and respond to gender-based harassment.

The suit comes a month after Grace Rebecca Mann, a 20-year-old member of the school’s Feminists United on Campus, was killed in her off-campus residence last month. One of the people she shared the home with, Steven Vander Briel, has been charged with first-degree murder. The suit does not accuse the Virginia school of being responsible for her death.

Members of Feminists United said in a complaint that they “suffered significant fear and anxiety”, because of threats and comments made by fellow students and that specific members of the group, including Mann, were harassed.

The complaint claims that at the school, there was “a systemic failure to protect them from a sexually hostile school environment, from sex-based cyber-assaults and from threats of physical and sexual violence”.

The complaint lists the club and five students as plaintiffs, including one whose name is redacted from the document. The Feminist Majority Foundation, which is affiliated with the campus group, is also a plaintiff.

The women say that they appealed to school staff and administrators for help after they became the subjects of violent threats and harassment on the anonymous social-networking app Yik Yak in response to Feminists United members speaking out about campus gender discrimination and sexual assault.

“The University condoned and ratified a sexually hostile environment by permitting ongoing, gender-based cyber-stalking and cyber-assaults” of members of Feminists United, according to the complaint.

In November 2014, Feminists United was involved with public discussions about the school’s decision to recognize fraternities and sororities. Plaintiff Paige McKinsey, president of the group, said she was then targeted on Yik Yak.

“Dandy’s about to kill a bitch … or two,” said one comment posted anonymously on the app. “Can we euthanize whoever caused this bullshit?” said another.

The school dissolved the men’s rugby team in March, though the video was uncovered in November 2014. According to the complaint, Feminists United members were accused of releasing the video and, over the course of several months, were subjected to harassment online and in person.

The women said that when they reached out to school leadership for help, “the administration took no action to protect them”. The complaint says Yik Yak also did not respond to complaints about the harassment.

The university has not responded to the Guardian’s request for comment. On Wednesday before the complaint was made public, the school released a statement to the New York Times:

“To the university’s knowledge, no known reports of direct threats of violence and/or sexual assault have gone unheeded,” the school said. “The University of Mary Washington’s No 1 priority has been and continues to be the creation and maintenance of a safe environment where all students can learn and grow.”

The suit calls on the school to implement policies to respond to “student-on-student gender-based harassment” and to cover costs incurred by the women, possibly including remediating transcripts and refunding tuition.

Meanwhile, questions still surround the circumstances of Mann’s death. She had attended a Day of Silence to raise awareness about bullying of sexual minorities on 17 April, the day she was killed.

Last month, her father, Fairfax County juvenile and domestic relations court judge Thomas Mann, told the Washington Post that authorities had not told the family the motive for the killing.

Vander Briel, 30, who is accused of strangling her to death, was a former school rugby player who attended the university on-and-off. He had been invited to move into the home in January.