A noose was found hanging, on Saturday afternoon, from a lamp post outside the National Gallery of Art in Washington, D.C. for the third time in recent weeks.
Previously, nooses– a symbol of racist lynchings – were found on the floor of an exhibit about segregation at the National Museum of African American History and Culture as well as hanging from a tree outside the Hirshhorn Museum.
All three museums are located next to each other between Capitol Hill and the Washington Monument.
The African American Museum was inaugurated in September 2016 by then-President Barack Obama, who commented that the facility relates the story of black America and "helps to tell a richer and fuller story of who we are."
The museum contains about 36,000 items that trace the journey of African Americans from slavery in the 1800s to the fight for civil rights in the 20 century, and beyond.
The National Museum of African American History and Culture is part of the Smithsonian, which comprises 19 museums – including the Hirshhorn – galleries and the National Zoological Park.
It had 30.2 million visits last year, according to its website.