When seven students were allegedly drugged at Stanford University’s Sigma Chi fraternity in Jan. 2018, the school responded by suspending the organization from campus in what a group of alumni has called an “absurd and unjust” punishment, according to a new lawsuit.

The group of alumni that owns the Sigma Chi house, called the Alpha Omega House Corporation, claim in their June 11 filing in Santa Clara County Superior Court that Stanford administrators ultimately sanctioned the frat over allegations that were never proven. The 60-page complaint was first reported by The Mercury News.

Sigma Chi is Stanford’s longest continuously operating fraternity.

A person “loosely affiliated” with the men’s rowing team—who was never a student at the university—may have brought drugs to the event on Jan. 12, 2018, The Stanford Daily reported at the time.

Investigations by the Sigma Chi International Fraternity organization, the Stanford Department of Public Safety, and the school’s Title IX office reportedly concluded in May 2018 that Sigma Chi members provided alcohol to underage students and did not follow university guidelines that should have mandated they register the party with administrators.

The investigations, however, did not conclusively determine that any drugging took place, according to the lawsuit.

“The AOHC has never been advised by Stanford, the police, the Title IX Office or the International Fraternity, that any responsible party has ever come to the conclusion that any drugs were introduced to student beers on the evening of this event,” according to the lawsuit.

In the aftermath of the probes, Sigma Chi’s Stanford chapter lost its charter in May 2018 and was placed on “suspended active status” by the school, which prohibited the organization from taking part in fraternity-sanctioned activities until 2021, The News reported. Stanford claimed at the time that the fraternity violated the school’s alcohol regulations, citing three different occasions in April 2014, Spring 2016, and the January 2018 party, the lawsuit states.

But Stanford did not suspend the party co-host, the Pi Beta Phi sorority, or discipline any members of the men’s rowing team, many of whom were present that night, the lawsuit claims.

The inconsistent disciplinary action makes Sigma Chi’s suspension both “absurd and unjust,” Alpha Omega alleges. What’s more, when Sigma Chi fought its suspension, the lawsuit reportedly claims that the fraternity was “denied the students the very due process they are promised in Stanford’s own policies.”

In addition to the suspension, a university administrator informed the Alpha Omega House Corporation in Feb. 2019 that Stanford would not be renewing the ground lease on the house and would award it to another Greek organization for the 2020-21 academic year.

Bob Ottilie, chairman and spokesman for Alpha Omega, claimed to The Mercury News on Monday that Stanford is using the fallout from the Jan. 2018 party “as the pretext to both get rid of our students charter and to take the last privately-owned house on campus.”

Stanford said in a statement on Monday that “the lease has terminated because AOHC is in violation of the lease’s requirement that the property only be used by AOHC to house active members of the alpha omega chapter.”

“Because the Alpha Omega Chapter’s charter has been suspended by the Sigma Chi International Fraternity and the chapter is no longer recognized by Stanford due to disciplinary measures imposed by Stanford, the chapter no longer has any active members and, therefore, the lease’s requirements are not being met,” the statement continued.

The university has said it will respond further to Ottilie’s allegations in court, and ultimately the legal battle will determine the fate of the Sigma Chi house.