(CNN) Three former Dartmouth College professors turned the school's Department of Psychological and Brain Sciences into a "21st Century Animal House," where female students were subjected to rape and sexual harassment, a federal lawsuit alleges.

Tenured professors Todd Heatherton, William Kelley, and Paul Whalen treated women as sex objects, the lawsuit from seven women claims. The men, who no longer are allowed on campus, coerced them into drinking and made the women feel as if their success depended on their willingness to go along with the "alcohol-saturated" culture the prominent researchers created, according to the complaint.

Kelley and Whalen have not responded to CNN's requests for comment. In a statement through his lawyer, Heatherton categorically denied "playing any role in creating a toxic environment at Dartmouth College," and said he was disturbed by the allegations. None of the plaintiffs were his graduate students, the statement adds.

The lawsuit, filed Thursday, comes as US universities continue to grapple with how to handle allegations of campus sexual misconduct and their obligations under Title IX, the federal law that bars discrimination based on sex, including harassment, in federally funded education programs and activities.

The US Department of Education in 2017 withdrew Obama administration guidance on how schools should handle sexual assault claims under Title IX, citing concerns that it denied due process rights to the accused. New guidance is expected soon.

The women are suing Dartmouth's trustees for $70 million in damages, based on allegations the Ivy League school breached its duty to protect them from sexual harassment. The suit also accuses the New Hampshire institution of failing to create an environment free from gender-based discrimination, in violation of Title IX.

"The seven Plaintiffs, each an exemplary female scientist at the start of her career, came to Dartmouth to contribute to a crucial and burgeoning field of academic study. Plaintiffs were instead sexually harassed and sexually assaulted by the Department's tenured professors and expected to tolerate increasing levels of sexual predation," the lawsuit states.

As many as 40 current and former female students may be eligible to join the class-action suit, plaintiffs' attorneys told CNN. Three of the women are still at Dartmouth, the suit states.

'Inclusive campus for all members'

The 72-page complaint offers the first graphic insights into allegations that first emerged publicly about a year ago with a report in The Dartmouth student newspaper . They range from one professor forcing a female student to have sex with him against her will to another professor sending a female student an unwanted photo of his erect penis, according to the lawsuit.

The suit alleges that women felt pressure to participate in a "predatory boys club" -- or risk their careers, because the men controlled resources in their labs.

New Hampshire Attorney General Gordon MacDonald in October 2017 announced a joint law enforcement investigation into the claims. The investigation is "active and ongoing," a spokesperson for the office said.

School officials also launched an inquiry that culminated in the resignations of Whalen and Kelley in June and July, the school said. Heatherton was on sabbatical leave during the investigation and chose to retire in June.

"Sexual misconduct and harassment have no place at Dartmouth," the school said in a statement to CNN. "Dartmouth's board of trustees and senior leadership team are dedicated to maintaining a safe and inclusive campus for all members of our community and we remain committed to improving our culture as we work to make our community the best it can be."

Heatherton last year addressed the claims, telling Slate he did his "best not to socialize with graduate students outside of the work setting, as the mentoring relationship should remain professional." The statement to CNN on Thursday said Heatherton was "extremely concerned about being grouped together with the other professors" and pointed out that the lawsuit's allegations predominantly involved Kelley and Whalen.

"He had no knowledge of the specific allegations that were made about them. He did not engage in the general patterns of conduct they are accused of," the statement says. "While at Dartmouth, Professor Heatherton did his best to support and promote the careers of all graduate students."

16 years of inaction, plaintiffs claim

The plaintiffs claim Dartmouth knew about the professors' behavior for more than 16 years and did nothing. Then in 2017, at least 27 people came forward in connection with formal claims of alleged sexual assault and sexual harassment by the three men.

Unnamed female graduate students, including all the women now suing Dartmouth, reported the claims to the college's Title IX office or attested to them, according to the suit and plaintiffs' lawyers.

During the Title IX investigation, Dartmouth failed to provide the plaintiffs with support, accommodations or guidance, then "unilaterally terminated" the disciplinary process, letting Heatherton retire and Kelley and Whalen resign, without seeking their input, the lawsuit claims.

In its statement, school officials said: "We applaud the courage displayed by members of our community within the Department of Psychological and Brain Sciences (PBS) who brought the misconduct allegations to Dartmouth's attention last year. And we remain open to a fair resolution of the students' claims through an alternative to the court process.

"However, we respectfully, but strongly, disagree with the characterizations of Dartmouth's actions in the complaint and will respond through our own court filings," they said.

'Mandatory fun' events alleged

The plaintiffs were mostly graduate students in a department known for its strong reputation and its professors' credentials, the suit states.

What the women found, according to the lawsuit, was a sexually hostile environment where the professors tied female students' success to their "willingness to tolerate unwanted sexual attention" and engage in frequent drinking binges.

Some plaintiffs described the consequences of resisting the professors' unwanted behavior. Plaintiff Annemarie Brown says she felt pressured to attend what Whalen called "mandatory fun" events, such as pajama parties and "boozy lunches" on workdays. When she refused, Whalen called her a "goody two shoes" and then began ignoring her academically, according to the lawsuit.

The professors "prided" themselves on having attractive women in their labs, the lawsuit claims. Kelley and Whalen openly debated who had "the hottest lab," and the three men routinely objectified women and commented on their appearances, according to the lawsuit.

Plaintiff Sasha Brietzke said Kelley treated her like a "doll" and often commented on the size of her breasts and complimented her makeup. He urged her to date his male friends "whom he instructed to flirt with Ms. Brietzke and give her hugs even after she expressed disinterest," the lawsuit says.

Heatherton denied that the professors tended to hire attractive research assistants. Hiring for his lab was conducted by his female lab manager, the statement said. "Research assistants were both men and women who were selected based on their interests and skills, not on their physical appearance."

He also denied regularly socializing with graduate students or attending any of the parties mentioned in the lawsuit. Lab meetings with students did not involve alcohol, the statement says.

As for an allegation in the complaint that he described, in a lab meeting, smiles from women as "socially rewarding," he said his words were misconstrued. He was in fact describing the Ph.D. thesis work of a male student "who found that smiles from people directed toward others activated brain regions involved in reward," the statement says.

"I don't appreciate how my description of research findings that were gender-neutral has been spun to imply hostile intent. It's just not true."

'Severe depressive episodes and a suicide attempt'

Kelley sent plaintiff Marissa Evans electronic messages of his naked body, including his erect penis, and pictures of himself engaged in sexual encounters with others, the lawsuit says. He regularly hosted "hot tub parties" at his house, which he dubbed "tubby time," late at night after drinking at bars, according to the lawsuit.

Evans grew fearful that Kelley would force her to have sex with him after he stated his intention to do so, the lawsuit says. She "was driven to severe depressive episodes and a suicide attempt," according to the lawsuit.

"Ms. Evans's experiences at Dartmouth have had a lasting effect on her professional career and mental health. Ms. Evans will only work in research labs run by women because of her deep distrust of male employers. She was forced to withdraw from her first semester in a postbaccalaureate premedical program due to mental health reasons resulting from her time at Dartmouth," the lawsuit says.

'She is plagued with doubts about her future'

The unwanted behavior allegedly continued after some of the plaintiffs reported it to college officials in April 2017. Weeks later, plaintiff Vassiki Chauhan says Whalen raped her, according to the lawsuit.

The assault occurred in Whalen's home after he pressured her to drink throughout the night, the lawsuit says. It goes on the say she strongly rejected his advances and tried to flee but he prevented her from leaving. He forced himself on her and when she asked him to use protection he refused, according to the lawsuit.

After she was sexually assaulted, she sought professional counseling services at Dartmouth's health center and shared intimate thoughts about the assault, the lawsuit said. During the Title IX inquiry, Chauhan provided her records to the school's investigator. According to the lawsuit, she was appalled to learn later from the Title IX report that the investigator showed her counseling records to Whalen and his attorneys without her consent.

"Ms. Chauhan feels so betrayed by that action that she cannot trust therapists enough to seek the treatment she knows she needs," the lawsuit claims. "She is plagued with doubts about her future prospects in academia and has lost her optimism for her well-being in personal relationships."