A memorial dedicated to slaves and African-American workers at the University of North Carolina at Chapel Hill was vandalized Sunday, the university said, as the university is still reeling from tensions over a Confederate monument that was toppled by protesters last year.

The memorial, called the Unsung Founders Memorial, was vandalized by two people, including one person with ties to a group called Heirs to the Confederacy, the university said.

The Unsung Founders Memorial was installed in 2005 to honor “those men and women of color — enslaved and free — who helped build the Carolina we all know and love,” according to the university. It features a stone tabletop six feet in diameter that is held up by 300 bronze figurines.

At about 1:30 a.m. Sunday, the memorial was defaced with urine and racist language written in permanent marker, the university police said.