A long-simmering feud between the mayor of Washington, DC, and the city’s cultural commission came to a boil late last week when commission staffers found themselves locked out of a vault holding thousands of artworks.

On Friday, the registrar of the District of Columbia Commission on the Arts and Humanities, Ron Humbertson, attempted to enter the storage facility but discovered that the locks had been changed, according to the Washington City Paper, which first reported the news. Inside the vault are around 3,000 works by local artists including Sam Gilliam and Alma Thomas, among others.

“Yes, apparently last Friday when [Humbertson] tried to access the art vault to get art for an installation, he could not get in,” according to a memo written by the chair of the agency. “It was a surprise as he (and no one to my knowledge) had a heads up.”

The paper said the move was an attempt from Mayor Muriel Bowser’s office “to seize the art collection.”

By the Tuesday after Labor Day weekend, access had still not been restored, and was granted only later in the week. Although the works in the vault are purchased by the commission, they legally belong to the DC government, according to the Office of the Deputy Mayor for Planning and Economic Development, making it unclear who precisely has control over the collection.

The lockout caps a longstanding dispute between DC Mayor Muriel Bowser, who has pushed hard to bring cultural funding under executive control, and the commission, which opposed several of her proposed moves.

Last fall, the office lobbied against legislation proposed by the mayor’s office that would have made the commission an advisory body rather than a funding arm.

The battle escalated when the DC council passed a motion to ensure the independence of the commission. Following that move, in August, Terrie Rouse-Rosario, the commissioner of the Arts and Humanities agency and an ally of Bowser, announced her resignation, effective September 30. She also announced the cancellation of the 34th annual Mayor’s Arts Awards and began staffing up her agency, despite her pending departure.