The National Park Service discovered graffiti on three monuments in Washington, D.C., over Presidents Day weekend, according to WRC-TV.
The outlet reported that small spaces at the Lincoln Memorial, the Washington Monument and the World War II Memorial were defaced.
Mike Litterst, a spokesperson for the National Park Service, said that they believe the three instances of graffiti are likely the work of one person, as they contain similar messages and the handwriting appears to be the same.
Litterst said the vandal used permanent or magic marker. He added that the park service is skilled at the difficult process of removing graffiti but must be cautious to not cause “further damage to the stone.”
He added that the park service is reviewing its security footage in the hopes of identifying the vandal.
WRC did not say what words the vandal wrote on the stone, but reports that they were not overtly political or hate-filled.