Barbara Ann Hartke, 81, filed a lawsuit against the Catholic University of America and Auction house Bonhams earlier this month, according to court records, as news of the dress' auction made headlines.
The blue-and-white checked frock with attached white blouse — seen on the ruby-slippered, tornado-transported Dorothy in the iconic 1939 film — was considered lost for nearly four decades before it was rediscovered last year in Catholic University's drama department collection.
Department head Father Gilbert Hartke received the dress as a gift back in the 1970s. But after just a year at the Washington, D.C., campus, the costume was reported to have mysteriously gone missing.
Fr. Gilbert died in 1986. It wasn't until May 2021, nearly four decades later, that the dress was found again in a discarded shoebox.
Dennis Van Tine/STAR MAX/IPx
Bonhams planned to put the dress up for sale on Tuesday, as part of their Bonhams Classic Hollywood: Film and Television sale in Los Angeles. They estimated the dress, one of only four of the original costume in existence and one of only two still including the white blouse, was valued between $800,000 and $1.2 million.
This particular dress, according to the auction house, was pinpointed as the one Garland wore in the iconic scene where Dorothy confronts the Wicked Witch of the West in her castle.
But Barbara Ann, Fr. Gilbert's niece and his closest living relative, claims she's the rightful owner of the costume. In her lawsuit, filed on May 3 and obtained by PEOPLE, she said actress Mercedes McCambridge in 1973 "specifically and publicly" gifted the garment to her uncle and that there is no documentation demonstrating that Fr. Gilbert "ever formally or informally donated the dress to Catholic University."
"The dress has great and substantial sentiment value to the plaintiff, is unique, and is recognized worldwide as an iconic image of perhaps the most beloved and watched film in the history of cinema," the suit states. "Catholic University apparently has made no attempt to locate decedent's heirs since the dress was relocated [and] has no ownership interest in the dress."
In an opposing filing, Catholic University's attorneys called Barbara Ann's request "unwarranted," pointing to Fr. Gilbert's vow as a Dominican priest "to never accept gifts in his personal capacity." That would mean, they argue, that it would be impossible to classify the dress as part of any family estate.
Additionally, they claimed that it is "pure speculation" that McCambridge, who died in 2004, "intended to gift the dress to [the priest] in he is personal capacity and that he so accepted." They also pointed to the failure of Fr. Gilbert's estate list "any personal or real property, nor tangible assets of any value, despite widespread knowledge of the dress at the time."
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Amid the debate, U.S. District Judge Paul Gardephe on Monday granted a motion for a preliminary injunction. The ruling means the auction of the dress will be postponed until the case is resolved.
A pretrial conference is currently scheduled for June 9.
"We look forward to presenting our position, and the overwhelming evidence contradicting Ms. Hartke's claim, to the Court in the course of this litigation," attorneys for Catholic University told PEOPLE in a statement, adding that the school is still "committed to its plan to use proceeds from a sale of the dress to endow a faculty position in the Rome School of Music, Drama and Art, which it believes is in line with Mercedes McCambridge's original intent and Father Gilbert Hartke's desire to support and grow the University's drama program."
"My client, an 81 year old woman and his closest living heir, believes the dress is the property of Father Hartke's estate and filed a complaint requesting that the auction be postponed until the court can determine ownership," a lawyer for Barbara Ann said to PEOPLE. "U.S. District Judge Gardephe of the Southern District of New York yesterday ruled that the auction could not take place until ownership was resolved, given the unique and historic nature of the Dorothy Dress."
Lawyers for Bonhams did not immediately respond to PEOPLE's request for comment.